Chemistry - Ms Greene

Front 1

Define the term atomic number?

Back 1

The number of protons in an atom

Front 2

Define the term mass number?

Back 2

The number of protons and neutrons in an atom

Front 3

What is an atom?

Back 3

The smallest components of an element showing its chemical properties

Front 4

What is the relative mass of an electron?

Back 4

1/1836

Front 5

What is an isotope?

What stays the same in an isotope?

Back 5

Isotopes are different forms of the same atom with different numbers of neutrons.

The number of protons always stays the same, otherwise it is not the same element.

Front 6

What does different numbers of neutrons do and not do?

Back 6

It changes the physical properties of an element but not its chemical properties

Front 7

What is heavy water?

Back 7

Heavy water is used in nuclear powerplants and uses heavier forms of hydrogen to make it

Front 8

Descibe the differance between ice made with heavy water and regular water?

Back 8

Heavy water has a higher density and so the ice will sink but regular water will float because its structure gives it a lower density than water

Front 9

The number in the name of different isotopes represents the elements what....?

Back 9

Mass number (number of protons and neutrons)

Front 10

What does A stand for?

Back 10

The atomic number

Front 11

What does z stand for?

Back 11

The mass number

Front 12

What does P+ stand for?

Back 12

Proton

Front 13

What does e- stand for?

Back 13

Electron

Front 14

What does n stand for?

Back 14

Neutron

Front 15

Why is the mass of chlorine in the periodic table 35.5?

Back 15

Because it takes an average of the mass of both chlorine-35 and chlorine-37, taking into account their relative abundance, of which chlorine-37 is lower and chlorine-35 is higher, therefore making the average 35.5

Front 16

What is a cation?

Back 16

When welectrons are lost from an atom, forming a positively chanrged ion

Front 17

What is a positively charged ion called?

Back 17

A cation

Front 18

What is an anion?

Back 18

When electrons are lost from an atom forming a negatively charged ion

Front 19

What is a negatively charged ion called?

Back 19

An Anion

Front 20

What are cations typically?

Back 20

Metals

Front 21

What are anions typically?

Back 21

Non metals

Front 22

What is an isoelectron?

Back 22

They are different elements as they have different numbers of protons and neutrons but the same number of electrons because they have lost or gained them

Front 23

What are elements with different numbers of protons and neutrons but the same number of electrons called?

Back 23

Isoelectrons

Front 24

What does m/z mean?

Back 24

mass/charge

Front 25

What are the two axis on a spectra?

Back 25

Mass over charge (along the bottom)

% abundance (along the side)

Front 26

What is the formula for calaculating the Ar (reltaive atomic mass) from a mass spectra?

Back 26

(% abundance x mass) + (% abundance x mass)

% abundance + % abundance

Front 27

What is the mass spectrometry process?

Back 27

1. Sample is placed in the mass spectrometer

2. The sample is vaporised and then ionised to form positive ions

3. The ions are accelerated, heavier ions move more slowly and are more difficult to deflect that lighter ions. So the ions of each isotope are separated

4. The ions are detected on a mass spectrum. Each ion reaching the detector adds to the signal so the greater the abundance the larger the signal

Front 28

Describe the interior of a mass sepectrometer?

Back 28

Its kept under a vacum to allow the ions to move at high speeds because they will not collide with atoms in the air.

It is also kept at a low pressure

Front 29

What is the formula for ammonium?

Back 29

NH4

Front 30

What is the charge on ammonium?

Back 30

1+

Front 31

What is the formula for hydroxide?

Back 31

OH

Front 32

What is the charge on hydroxide ions?

Back 32

1-

Front 33

What is the formula for nitrate?

Back 33

NO3

Front 34

What is the charge on a nitrate ion?

Back 34

1-

Front 35

What is the formula for a nitride ion?

Back 35

NO2

Front 36

What is the charge on a nitride ion?

Back 36

1-

Front 37

What is the formula for an ion of hydrogencarbonate?

Back 37

HCO3

Front 38

What is the charge on an ion of hydrogencarbonate?

Back 38

1-

Front 39

What is the formula for an ion of manganate (VII) (permanganate)?

Back 39

MnO4

Front 40

What is the charge of a manganate (VII) (permanganate) ion?

Back 40

1-

Front 41

What is the formula for a carbonate ion?

Back 41

CO3

Front 42

What is the charge on a carbonate ion?

Back 42

2-

Front 43

What is the formula for a sulfate ion?

Back 43

SO4

Front 44

What is the charge on a sulfate ion?

Back 44

2-

Front 45

What is the formula of a sulfite ion?

Back 45

SO3

Front 46

What is the charge on a sulfite ion?

Back 46

2-

Front 47

What is the formula for a dichromate (VI) ion?

Back 47

Cr2O7

Front 48

What is the charge on a dichromate (VI) ion?

Back 48

2-

Front 49

What is the formula for a phospate ion?

Back 49

PO4

Front 50

What is the charge on a phosphate ion?

Back 50

3-

Front 51

What is the negligible mass of an electron?

Back 51

1/1836 of a proton

Front 52

Where is nearly all the mass of an atom?

Back 52

In the nucelus

Front 53

What is the role of neutrons in the nucleus?

Back 53

They hold the nuceleus together despite the electrostatic repulision between its positively charged protons

Front 54

Describe neutrons in the nucelus?

Back 54

1. Most atoms contain the same number of, or slightly more neutrons than protons

2. As the nucelus gets larger more and more neutrons are needed

Front 55

What identifies an element?

Back 55

The number of protons in an atom

Front 56

Describe atoms of the same element?

Back 56

Every atom of the same element has the same numbers of protons

Front 57

Describe atoms of different elements?

Back 57

Different atoms contain different numbers of protons

Front 58

What are isotopes?

Back 58

They are atoms of the same element with different numbers of neutrons and different masses

Front 59

What are most elements made up of?

Back 59

A mixture of isotopes

Front 60

What represents the mass number of an isotope?

What represents the atomic number of an isotope?

Back 60

A

Z

Front 61

Describe isotopes and the way in which they react?

Back 61

1. Different isotopes of the saem element have the same number of electrons

2. The number of neutrons has no effect on the reactions of an element

3. Different isotopes of an element therefore react in the same way

Front 62

What is an ion?

Back 62

It is a charged atom. This is formed from the loss or gain of electrons and because the number of electrons is different to the number of protons

Front 63

What are positive ions also called?

Describe positive ions?

Back 63

Cations

They are atoms with fewer electrons than protons. They have an overall positive charge

Front 64

What are negative ions called?

Describe negative ions?

Back 64

They are called anions

They are atoms with more electrons than protons. They have an overall negative charge

Front 65

Describe the strong nuclear forces within an atom and the consequence of this?

Back 65

The strong nuclear forces holding together protons and neutrons results in the loss of a fraction of their mass. This is called the mass defect

Front 66

What is the role of carbon-12?

Back 66

It is the standard isotope which is the international standard for the measurement of atomic masses

Front 67

What is an atomic mass unit?

Back 67

u

Front 68

What is the mass of carbon 12?

Back 68

12 u (atomic mass units)

Front 69

What is the standard mass of atomic mass and how does this relate to carbon-12?

Back 69

The standard mass for atomic mass is 1u, the mass of 1/12th of an atom of carbon-12

Front 70

What is the definition of relative atomic mass?

Back 70

It is the weighted mean mass of an atom of an element relative to 1/12th the mass of an atom of carbon-12

Front 71

What does the weighted mean mass of an element take into account?

Back 71

1. The percentage abundance of each isotope

2. The relative isotopic mass of each isotope

Front 72

What equipment is used to find the percentage abundances of the isotopes in a smaple of an element?

Back 72

Using a mass spectrometer

Front 73

What is the mass to charge ratio?

Back 73

It is how the ions are detected on a mass to charge ratio

m/z

relative mass of an ion/relative charge on an ion

Front 74

What is a binary compound?

Back 74

It contains only two elements

Front 75

How do you name a binary compound?

Back 75

1. The metal ion comes first

2. Change the ending of the second elements name to -ide

Front 76

List the diatomic molecules?

Back 76

H2, N2, O2, F2, CL2, BR2, I2

Front 77

Give the forula of phosphorus and sulfur?

Back 77

P4 and S8 (in pratice sulfur is just written as S

Front 78

What is the formula unit?

Back 78

The formula worked out from the ionic charges of ionic compounds

Front 79

What is the shell number of energy level called?

Back 79

The quantum number/level

Front 80

What are shells made up of?

Back 80

Shells are made of atomic orbitals.

Front 81

Describe atomic orbitals

Back 81

1. Regions around the nucelus that can hold up to two electrons with opposite spins.

2. Atomic orbitals are regions where there is a high probability of finding an electron

3. Can hold 1 or 2 electrons

4. There are s-, p-, d- and f- orbitals

5. Each orbital has a different shape

Front 82

Describe s-orbitals?

Back 82

1. The shape is of a sphere

2. Each shell from quantum level 1 contains 1s orbital

2.The greater the shell number the greater the radius of the s orbital

Front 83

Describe p orbitals?

Back 83

1. The electron cloud is in the shape of a dumb-bell

2. There are three separate p orbitals at right angles to each other, called Px, Py and Pz

3. Each shell from quantum level 2 contains three p orbitals

4. The greater the shell number, the further the p-orbital is from the nucleus

Front 84

Describe d orbitals?

Back 84

Each shell from quantum level 3 contains five d orbitals

Front 85

Describe quanutm level f?

Back 85

Each shell from quatum level 4 conatins seven f orbitals

Front 86

How are obitals grouped together?

Back 86

As sub shells

Front 87

How mnay electrons can fit in the sub shell or an...

1. S orbital

2. P orbital

3. D orbital

4. F orbital

Back 87

1. 2

2. 6

3. 10

4. 14

Front 88

Describe the energy levels of quantum level 2 sub shells?

Back 88

Each new sub shell added has a higher energy. In the second shell the 2p sub shell has a higher energy level that the 2s sub shell

Front 89

Describe the energy level of the quantum level 3d sub shell and 4s?

Back 89

1. The highest energy level in the third and the lowest energy in the fourth shell overlap

2. The 3d subshell is at a higher energy level than a 4s sub shell

3. The 4s subshell therefore fills before the 3d subshell

4. The order of filling is therefore 3p, 4s, 3d

Front 90

Describe electrons and electron spin?

Back 90

1. Electrons are negatively charged and repel one another

2. They have a property called spin - either up or down

3. An electron is shown as an arrow, indicating the direction of its spin

4. The two electrons in an orbital must have opposite spins

Front 91

Why must two electrons in a sub shell have opposite spins?

Back 91

Because the oppositecharged help to counteract the repulision between the negative charges of the two electrons

Front 92

Describe the filling of orbitals and electron spin diagrams?

Back 92

1. The orbitals have the ame energy

2. One electron occupies each orbital before pairing starts

3. This prevents any repulsion between paired electrons until there is no further orbital available at the same energy level

Front 93

Where is D Block on the periodic table?

Back 93

Front 94

Where is S Block on the periodic table?

Back 94

And helium

Front 95

Where is F Block on the periodic table?

Back 95

Front 96

Where is P Block on the periodic table?

Back 96

Front 97

Describe ions and the 4s shell?

Back 97

1. The 4s sub shell is at a lower energy level than the 3d sub shell so it is filled first

2. The 4s sub shell also empties before the 3d sub shell

Front 98

Describe the energy level of the 3d and 4s sub shells once filled?

Back 98

The energies of the 3d and 4s sub shells are very close together and once filled the 3d energy level falls below the 4s

Front 99

Here is the electronconfiguration of the nickel atom:

1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^8

Describe the electronic configuration of a Ni^2+ ion

Back 99

1s^2 2s^2 2p^6 3s^2 3p^63d^8

This is because the 4s shell empties before the 3d sub shell

Front 100

Which two elements in the d block have special properties?

Back 100

Copper and Chromium

Front 101

Describe the electron configuration of copper?

Back 101

Electron spin attempts tom combat the repulsive charges between negatively charged electrons. Therefore copper fills such that

[Ar]4s1 3d5

The 3 fills an extra electron and the 4 loses one

Front 102

Describe the electron configuration of chromium?

Back 102

Electron spin attempts tom combat the repulsive charges between negatively charged electrons. Therefore copper fills such that

[Ar]4s1 3d10

The 3 fills an extra electron and the 4 loses one

Front 103

What is ionic bonding?

Back 103

It is the electrostatic forces of attraction between positive and negative ions. It holds together cations and anions

Front 104

What do you need to rember to do when drawing a dot and cross diagram?

Back 104

Put the brackets round the outside

Front 105

Describe the structure of ionic bonds?

Back 105

1. Each ion attracts oppositley charged ions in all directions

2. This forms a giant ionic lattice containing billions of ions

3. The number of ions is determined by the size of the crystal

Front 106

Describe the physcial properties of ionic compounds?

Back 106

1. High melting and boiling points

2. Depends on the compounds - but they tend to dissolve

3. As a solid they do not conduct electricity

4. As molten or dissolved they conduct electricity

Front 107

Describe ionic compounds and their melting and boiling points?

Back 107

1. Most are solid at room temperature

2. This is because there is insufficient energy to overcome the strong electrostatic forces of attraction between the oppositely charged ions

3. High temperatures are needed to provide this quantity

4. They therefore have high melting and boiling points

Front 108

Describe the melting and boiling points for lattices conatining ions with greater ionic charges?

Back 108

The greater the charge the more energy is required required to overcome them so therefore they have a higher melting and boiling point than a ionic compound consisting of a lattice with a lesser charge

Front 109

What does ionic attraction depend upon?

Back 109

1. The quanitity of charge on an ion

2. The size of the ions

Front 110

Describe ionic compounds and solubility?

Back 110

1. Many ionic compounds dissolve in polar solvents such as water

2. The polar water molecules break down the lattice and surround each ion in solution

3. In a compound made of ions with large charges the ionic attraction may be too strong for the water to break down the lattice structure so the compound is not very soluble

Front 111

What are the two main processes for solubility of ionic lattices?

Back 111

1. The ionic lattice must be broken down

2 The water molecules must attract and surrond the ions

Front 112

What does the solubility of an ionic compound depend upon to happen?

Back 112

1. The relative strengths of the attractions within the giant ionic lattice

2. The attractions between ions and water molecules

Front 113

Describe ionic compounds and electrical conductivity?

Back 113

1. In a solid state an ionic compound does not conduct electricity

2. Once melted the ionic compound does conduct electricity

Front 114

Why can electricity not be conducted in a solid state of ionic lattice?

Back 114

1. The ions are in a fixed position in the gaint lattice

2. There are no mobile charge carriers

Front 115

Why can electricity be conducted in a liquid state of ionic lattice?

Back 115

1. The solid ionic lattice breaks down

2. The ions are now free to move as mobile charge carriers

3. This means an ionic compound is a conductor of electricity in liquid and aqueous states

Front 116

What is covalent bonding?

Back 116

It is the strong electroststic attraction between a shared pair of electrons and the nuclei of bonded atoms

Front 117

In which atoms does covalent bonding take place?

Back 117

1. Non metallic elements

2. Compounds of non metallic elements

3. Polyatomic ions

Front 118

What are pairs of electrons that are not shared in covalent bonds called?

Back 118

Lone pairs of electrons

Front 119

How mnay bonds does carbon form

How many bonds does oxygen form?

Back 119

4 bonds

2 bonds

Front 120

How many bonds does nitrogen form?

How many bonds does hydrogen form?

Back 120

3 bonds

1 bond

Front 121

Describe a double bond?

Back 121

1. The electrostatic forces of attraction are between two shared pairs of electrons and the nuceli of the bonding atoms

2. All atoms have 8 electrons in their outer shell

Front 122

Describe tripple covalent bonds?

Back 122

1. The electrostatic attraction is between three shared pairs of electrons and the nuclei of bonding atoms

2. All atoms have the structure of the nearest nobel gas

Front 123

What is a dative covalent bond?

Back 123

It is a covalent bond in which the shared pair of electrons has been supplied by one of the bonding atoms only

Front 124

What is a dative covalent bond also called?

Back 124

A coordinate bond

Front 125

What is covalent bond in which the shared pair of electrons has been supplied by one of the bonding atoms only called?

Back 125

A dative covalent bond

Front 126

Describe the electrons in dative covalent bonds?

Back 126

The shared pair of electrons by the sole bonding atom was originally a lone pair of electrons.

Front 127

What symbol indicates a dative covalent bond?

Back 127

an arrow from the sole bonding atom to the atom which gains electrons

Front 128

What is an oxidising agent?

Back 128

An oxidizing agent is a substance that has the ability to oxidize other substances (cause them to lose electrons)

Front 129

How many electrons are there in a....

1. S orbital

2. P orbital

3. D orbital

4. F orbital

Back 129

1. 2

2. 6

3. 10

4. 14

Front 130

Define an orbital?

Back 130

Atomic orbitals are regions of space around the nucleus of an atom where an electron is likely to be found.

Front 131

Define a covalent bond?

Back 131

A shared pair of electrons, one electron being supplied by each atom either side of the bond.

Front 132

What is the forumla of propene?

Back 132

C3H6

Front 133

What is another name for a dative covalent bond?

Back 133

A co-ordinate bond

Front 134

Describe the differences between silicon dioxide and carbon dioxide?

Back 134

1. Silicon dioxide is a macromoleucle, carbon dioxide is a simple covalent substance.

2. Silicon atoms in silicon dioxide are bonded to four other oxygen atoms, forming the crystal structure whereas carbon dioxide exists as lone molecules which are joined together by weak covalent bonds

Front 135

Describe electron pair replusion theory?

Back 135

1. An electron has a negative chage so electron pairs repel one another

2. Model used in chemsitry for expalining and predicitng the shaopes of molecules and polyactomic ions

Front 136

Describe the laws of the electron pair repulision theory?

Back 136

1. The electorn pairs surronding a central atom determine the shape of the molecule or ion

2. The elctron pairs repel one another so they are arranged as far apart as possible

3. The arrangement of electron pairs minimises repulision and thus holds the bonded atoms in a defintie shape

4. Different numbers of electron pairs result in different shapes

Front 137

What does this line represent in terms of shapes of molecules?

Back 137

A bond in the plane of the paper

Front 138

What does this line represent in terms of shapes of molecules?

Back 138

A bond that comes out of the plane of the paper

Front 139

What does this line represent in terms of shapes of molecules?

Back 139

A bond that goes into the plane of the paper

Front 140

Describe lone electrons and their positioning?

Back 140

1. Slightly closer to the central atom

2. Occupy more space than a bonded pair

Front 141

Describe the main difference between bonding and lone pairs?

Back 141

Lone pairs repel more strongly than a bonded pair

Front 142

Describe the relative repulsions between lone and bonding pairs?

Back 142

1. Bonded/bonded pair

2. Bonded pair/lone pair

3. Lone pair/lone pair (Strongest repulsion)

Front 143

Draw a triangular bipyramid?

Back 143

Front 144

Draw an octahedral?

Back 144

Front 145

Draw a linear?

Back 145

Front 146

Draw a trigonal Planar?

Back 146

Front 147

Draw a tetrahedral?

Back 147

Front 148

What is the name of the shape of a molecule with 2 electron pairs?

What are the bond angles?

Back 148

Linear

180 degrees

Front 149

What is the name of the shape of a molecule with 3 electron pairs?

What are the bond angles?

Back 149

Trigonal Planar

120 degrees

Front 150

What is the name of the shape of a molecule with 4 electron pairs?

What are the bond angles?

Back 150

Tetrahedral

109.5 degrees

Front 151

What is the name of the shape of a molecule with 5 electron pairs?

What are the bond angles?

Back 151

Triangular Bipyramid

90 and 120 degrees

Front 152

What is the name of the shape of a molecule with 6 electron pairs?

What are the bond angles?

Back 152

Octahedral

90 degrees

Front 153

What shape is CH4 (methane)?

Back 153

It has four bonding pairs so is tetrahedral

Front 154

What is the name of the shape with 2 bonding pairs and 1 lone pair?

Back 154

Bent

Front 155

What is the name of the shape with 3 bonding pairs and 1 lone pair?

Back 155

Trigonal pyramidal

Front 156

What is the name of the shape with 2 bonding pairs and 2 lone pairs?

Back 156

Non-linear or bent

Front 157

What is the name of the shape with 4 bonding pairs and 1 lone pair?

Back 157

Seesaw

Front 158

What is the name of the shape with 3 bonding pairs and 2 lone pairs?

Back 158

T-shaped

Front 159

What is the name of the shape with 2 bonding pairs and 3 lone pairs?

Back 159

Linear

Front 160

What is the name of the shape with 5 bonding pairs and 1 lone pairs?

Back 160

square pyramidal

Front 161

What is the name of the shape with 4 bonding pairs and 2 lone pairs?

Back 161

square planar

Front 162

Draw a bent molecule?

Back 162

Front 163

Draw a trigonal pyrmidal molecule?

Back 163

Front 164

Draw a T shape molecule?

Back 164

Front 165

Draw a see saw molecule?

Back 165

Front 166

Draw a square planar molecule

Back 166

Front 167

Draw a square pyramidal molceule?

Back 167

Front 168

Draw a square planar molecule?

Back 168

Front 169

When you have two double bonds... how many bonded pairs is this equal to?

Back 169

Two

Front 170

Describe the shape of CO2?

Back 170

1. The 4 bonded pairs around the central carbon atom are two double bonds so there are two bodning regions

2. The two bonded regions repel as far apart as possible giving the molecule a linear shape

Front 171

The greater the number of electron pairs....

Back 171

... the smaller the bond angles

Front 172

Describe the covalent bond between atoms of different elements? (related to electronegativity)

Back 172

1. The nuclear charges are different

2. The atoms may be different sizes

3. The shared pair of electrons may be closer to one atom than the other

Front 173

What is electronegativity?

Back 173

A measure of the attraction of a bonded atom for the pair of electrons in a covalent bond

Front 174

On what scale is electronegativity measured?

Back 174

On the Pauling scale

Front 175

What does a large pauling value indicate?

Back 175

That the atoms of the element are very electronegative

Front 176

How does electronegativity increase in the periodic table (in what directions)?

Back 176

Across and up the periodic table

Front 177

Why does electronegativity increase across the periodic table?

Back 177

Because the nuclear charge increases (the number of protons in the nucleus)

The atomic radius decreases

Front 178

What is the most electronegative atom?

What is the value?

Back 178

Fluroine

4.0

Front 179

What happens when electronegatibity is large?

Back 179

1. One bonded atom will have a much greater attraction for the shared pair than the other bonded atom.

2. The more electronegative atom will have gained control of the electrons and then bond will now be ionic rather than covalent

Front 180

What is the electronegativity difference of a covalent bond?

Back 180

0

Front 181

What is the electronegativity difference of a polar covalent bond?

Back 181

0 to 1.8

Front 182

What is the electronegativity difference between an ionic bond?

Back 182

Greater than 1.8

Front 183

In a non polar bond describe the bonded electron pair?

Back 183

The bonded electron pair is shared equally between the bonded atoms

Front 184

When is a bond non polar?

Back 184

1. The bonded atoms are the same

2. The bonded atoms have the same or similar electronegativity

Front 185

What is a pure covalent bond?

Back 185

Pure covalent bonds exist when there is no difference between the two atoms sharing the electrons. The electronegativity of the two atoms is identical.

Front 186

Describe the electronegatiity of hydrocarbons?

Back 186

Crabon and hydrogen atoms have a very similar electonegativities and form non polar bonds.

Front 187

Describe hydrocarbon liquids and water?

Back 187

They are non polar solvents and do not mix with water

Front 188

Describe the bonded electron pair in a polar bond?

Back 188

The bonded electron pair is shared unequally between the bonded atoms

Front 189

What is a polar covalent bond?

Back 189

When the bonded atoms and different and have different electronegativity values

Front 190

Describe the bonding in HCl, hydrogen hads an electronegatiity of 2.1 and chlorine has an electrogegativity of 3.0?

Back 190

1.The chlorine atom is more elctronegative than the hydrogen atom

2. The chlroine atom has a greater attraction for the bonded pair of electrons than the hydrogen atom, resulting in a polar covalent bond

3. The HCL bond is polarised with a small partial charge on the hydrogen atom and a small partial negative charge on the chlorine atom

Front 191

What does 𝛿 stand for?

What does it mean?

Back 191

It stands for delta

It means smalls

Front 192

describe the difference between𝛿+, 𝛿- and + and -?

Back 192

The two charges 𝛿+ and 𝛿- are partial chanrges and therefore are much smaller than the full charge

Front 193

What is the seperation of opposite charges called?

Back 193

A dipole

Front 194

Describe the dipole in a polar covalent bond?

Back 194

it does not change and is called permenent dipole

Front 195

Is HCL polar or non polar?

Back 195

It is polar

Front 196

Describe the polarity of molecules with more than two atoms?

Back 196

There may be two or more polar bonds. Depending on the shape of the molecule, the dipoles may reinforce one another to produce a larger dipole over the whole molecule, or cancel out the dipoles if they act in opposite directions

Front 197

Describe the polarity of the H2O molecule?

Back 197

1. The two O-H bonds each have different permanent dipoles

2. The two dipoles act in different directions but do not oppose each other

3. Overall the oxygen end of the molecule has a𝛿- charge and the hydrogen end of the molecule has a𝛿+ charge so it is polar

Front 198

Describe the polarity of a CO2 molecule?

Back 198

1. The two C--O bonds each have apermenant dipole

2. The two dipoles act in opposite directions and exactly oppose one another

3. The dipoles cancel and the overal dipole is 0 meaning it is non-polar

Front 199

In an ionic bond being dissolved in water, what are the metal ions attracted to, and what are the non metal ions attarcted to?

Back 199

The metal ions are positive and attracted to the oxygen of the water

The non metal ions are negative and attracted to the hydrogen of the water

Front 200

What do covalent bonds do?

Back 200

They holds the atoms in a molecule together

Front 201

What are intermolecular forces?

Back 201

They are weak interactions between dipoles of different molecules

Front 202

What are the three categories that intermolecular forces fall into?

Back 202

1. Induced dipole dipole interactions (London forces)

2. Permanent dipole dipole interactions

3. Hydrogen bonding

Front 203

What are intermolecular forces responsible for?

What are covalent bonds responsible for?

Back 203

The physical properties such as melting and boiling points

Determining the identity and chemcial reactions of molecules

Front 204

What are the units of bond enthalpy?

Back 204

KJmol^-1

Front 205

What is the bond enthalpy of London forces?

Back 205

1-10 KJmol^-1

Front 206

What is the bond enthalpy of permanent dipole-dipole interactions?

Back 206

3-25KJmol^-1

Front 207

What is the bond enthalpy of hydrogen bonds?

Back 207

10-40 KJmol^-1

Front 208

What is the bond enthalpy of single covalent bonds?

Back 208

150-500 KJmol^-1

Front 209

What are london forces?

Back 209

They are weak intermolecular forces that exist between all molecules, whether polar or non polar. The act between induced dipoles in different molecules

Front 210

What is the difference between Intermolecular forces and intramolecular forces?

Back 210

Intermolecular forces are forces of attraction between two or more molecules

Inbtramolecular forces are forces in a compound, such as covalent, ionic and metallic bonds

Front 211

Describe the origin of induced dipoles?

Back 211

1. Movement of electrons produces a changing dipole

2. At any instant an instant dipole will exist but its position is constantly shifting

3. The instant dipole induces a dipole o na neighbouring molecules

4. This induced dipole induces further dipoles on neighbouring molecules, which then attract one another

Front 212

Describe the time period of induced dipoles?

Back 212

They are temporary. In the next instant of time, the induced dipoles may disappear, only for it to take place again amongst other molecules

Front 213

What is the effect of increasing the number of electrons of the strength of induced dipole dipole interactions?

Back 213

1. The larger the instant and induced dipoles

2. The greater the induced dipole-dipole interactions

3. The stronger the attractive forces between the molcules

Front 214

What is the electronegativity value that is large enough to allow different elements in a molcule to be polar?

Back 214

0.5

Front 215

Describe the difference between the boiling point of helium and argon? (dipoles)

Back 215

Larger numbers of electrons in argon mean larger induced dipoles than in helium. This means that more energy is needed to overcome the intermolecular forces, so the boiling point of argon is greater than helium

Front 216

What is it recommended that van der Waal's forces relate too?

Back 216

Used to both permanent and induced dipole-dipole interactions

Front 217

What is the correct term to use when describing dipole dipole interactions?

What else can be used to describe them?

Back 217

London forces

Dispersion forces

Front 218

What do permeanent dipole dipole interactions act between?

Back 218

The permenant dipoles in different polar molecules

Front 219

Describe why the boiling point of F-F is less than H-Cl?

Back 219

1. Fluroine molecules are non polar and only have london forces between molecules

2. Hydrogen choride molecules are polar and have london forces and permanent dipole dipole interactions between molcules

3. Extra energy is required to break the additional permenant dipole dipole interactions between hydrigen chloride molecules

4. The boiling point of Hydrogen Chloride is therefore higher

Front 220

What is a simple molecular substance made up of?

Back 220

Simple molecules, containging a definite number of atoms with a definite molecular formula

Front 221

What do simple molecules form in solid state?

Back 221

A simple molecular lattice

Front 222

Describe a simple molecular lattice?

Back 222

1. The molecules are held in place by weak intermolecular forces

2. The atoms within each molecule are bonded together strongly by covalent bonds

Front 223

What are the bonds in all simple molecular substances?

Back 223

They are all covalently bonded

Front 224

What can simple molecular susbstances exist as at room temperature?

Back 224

Soilds, liquids or gases

Front 225

Why do simple molecular susbstances have low melting and boiling points?

Back 225

Because in a simple molecular lattice the weak intermolecular forces can be broken even by the energy present at low temperatures

Front 226

What happnes when a simple molecular lattice is broken apart during melting?

Back 226

1. Only ther weak intermolecular forces break

2. The covalent bonds are strong and do not break

Front 227

What are the two categorise that covalent substances with simple molecular sturcture fall into?

Back 227

Polar and non polar

Front 228

Which type of simple molecular structure is it easiert to predict the solubility of?

Back 228

Non polar substances

Front 229

What causes a molecule to be polar?

Back 229

When the ends of a molecule - called dipoles - carry an unequal distribution of charge

Front 230

Describe atoms with a high electrongeativity?

Back 230

An atom with a high electronegativity will tend to attract bonded electrons towards it.

Front 231

Describe atoms with a low electronegativity?

Back 231

An atom with a low electronegativity will have a very weak attraction for electrons.

Front 232

Draw electronegativity in a periodic table?

Back 232

Front 233

Describe the trends in electronegativity values in the periodic table?

Back 233

1. Increase from left to right across a period in the periodic table

2. Decrease on descending a group.

Front 234

Why is fluroine the most electronegative element?

Back 234

1. Fluorine is so close to ideal electron configuration, the electrons are held very tightly to the nucleus

2. It has the smallest atomic radius of the halogens.

3. Because the protons are closer to the outermost shell of Fluorine so the strength of the pull is higher towards the electrons

Front 235

Describe the relationship between ionisation energy and electronegativity?

Back 235

Atoms with greater electronegativities also have greater ionization energies

Front 236

Why does charge across a period increase (left to right)?

Back 236

Electronegativity increases across a period because the number of charges on the nucleus increases as the number of protons increases. That attracts the bonding pair of electrons more strongly.

Front 237

What does the attraction a bonding pair of electrons feels for a nucleus depend upon?

Back 237

1. The number of protons in the nucleus as these are what attract electrons

2. The distance the outer shell is from the nucleus

3. The amount of shielding created by inner electrons

Front 238

Why does electronegativity decrease down the group?

Back 238

As you go down a group, electronegativity decreases because the bonding pair of electrons is increasingly distant from the attraction of the nucleus as the number of shells increase and the shielding of inner electrons increases

Front 239

What happens when a non polar simple molecular substance is added to a non polar solvent?

Back 239

1. Intermolecular forces form between the molecules and the solvent

2. The interactions weaken the intermolecular forces in the simple molecular lattice, causing it to break and the coumpound to dissolve

Front 240

What happens when a non polar simple molecular substance is added to a polar solvent?

Back 240

1. There is little interaction between the molecules in the lattice and the solvent molecules

2. The intermolecular bonding within the polar solvent is too strong to be broken

Front 241

Describe the typical trend in simple molecular substances?

Back 241

They tend to be insoluble in polar solvents as many are non polar

Front 242

Why can polar covalent subsatances dissolve in polar solvents?

Back 242

Because the polar solute molecules and the polar solvent molecules can attract each other

Front 243

Name some common polar bonds, allowing solutes to dissolve in solvents?

Back 243

O-H bonds

H-Cl bonds

Front 244

What does the solubility of a polar solute in a polar solvent depend upon?

Back 244

The strength of the dipole

Front 245

What chains can molecules contain that make them non polar?

Back 245

Carbon chains

Front 246

Describe the solubility of a molecule if it contains both O-H bonds and H-Cl bonds?

Back 246

They are soluble in both polar and non polar substances

Front 247

What do the hydrophyllic ends of a biological molecule contain that makes them polar?

Back 247

An electronegative atom such as oxygen as this can interact with the water

Front 248

What do the hydrophobic ends of a biological molecule contain that makes them non polar?

Back 248

They are comprised of a carbon chain

Front 249

Describe simple molecular structures and conductibg electricity?

Back 249

1. There are no mobile charged particles in simple molecular structures

2. With no charged particles that can move there is nothing to complete an electrical circuit

3. Therefore simple molecular structures are non conductors of electricity

Front 250

What is an atomic orbital?

Back 250

A region around the nucelus than can hold us to two electrons with opposite spins

Front 251

What is a bond angle?

Back 251

The angle between two bonds at an atom

Front 252

What is a bonded pair?

Back 252

A pair of electrons shared between two atoms of make a covalent bond

Front 253

What is a coordinate bond?

Back 253

A shared pair of electrons in which the bonded pair has been provided by one of the bonding atoms only, also called a dative covalent bond

Front 254

Define a covalent bond?

Back 254

The strong electrostatic attraction between a shared pair of electrons and the nuceli of the bonded atoms

Front 255

What is a delocalised electron?

Back 255

Electrons that are shared between more than two atoms

Front 256

Define a dipole?

Back 256

A separation in electrical charge so that one atom of a polar covalernt bond, or one end of a polar molecule has a small positive charge, and the other has a small negative charge

Front 257

Define electron coniguration?

Back 257

A shorthand representation that shows how electrons occupy sub shells in an atom

Front 258

Define electronegativity?

Back 258

A measure of the attraction of a bonded atom for the pair of electrons in a covalent bond

Front 259

Define a giant covalent lattice?

Back 259

A three dimensional sturcture of atoms, bonded together by strong covalent bonds

Front 260

Define a giant ionic lattice?

Back 260

A three dimensional sturcture of oppostiley charged ions, bonded together by strong ionic bonds

Front 261

Define a giant metallic lattice?

Back 261

A three dimensional sturcture ofpositive ions and delocalised electrons, bonded together by strong metalic bonds

Front 262

Define a group?

Back 262

A vertical column in the periodic table. Element is a group have similar chemical properties and their atoms have the same number of outer shell electrons

Front 263

Define a hydrogen bond?

Back 263

A strong dipole dipole attraction between an electron deficient hydrogen atom of -NH, -OH or HF on one molecule and a lone oaur of electrons o a highly electronegative atom containing N,O or F on a different molecule

Front 264

Define an induced dipole-dipole interaction?

Back 264

Attractive forces between induced dipoles in different molecules also called London forces

Front 265

Define an intermolecular force?

Back 265

An attractive force between molecules. Intermolecule forces can be London forces, permanent dipole dipole interaction or hydrogen bonding

Front 266

Define an ion?

Back 266

A positvely or negatively charged atom ir a (covalently bonded) group of atoms (a polyatomic ion), where the number of electrons is different from the number of protons

Front 267

Define ionice bonding?

Back 267

The electrostatic attraction between positivie and negative ions

Front 268

Define isotopes?

Back 268

Atoms of the same element with different numbers of neutrons and different masses

Front 269

Defune a lone pair?

Back 269

An outer shell pair of electrons that is not involved in chemcial bonding

Front 270

Define the mass number?

Back 270

The sum of the numberof protons and neutrons in the nucelus, also known as the nuceleon number

Front 271

Define a metallic bond?

Back 271

The electrostatic attraction betweren positive metal ions and delocalised electroms

Front 272

What is the moblie phase?

Back 272

The phase that moves in chromotography

Front 273

Define a molecular ion?

Back 273

The positive ion formed in mass spectromerty when a molecule loses an electron

Front 274

Define a molecule?

Back 274

The smallest part of a covalent compound that can exist while retaining its chemical identity, consisting of two or moe atoms covalently bonded together

Front 275

Define non polar?

Back 275

With no charge separation across a bond or in a molecule

Front 276

Define Pualing electronegativity value?

Back 276

A value assigned as a measure of the relative attraction of a bonded atoms for the pair of electrons in a covalent bond

Front 277

Define a period?

Back 277

A horizontal row of elements in the periodic table. Elements show trend in properties across a period

Front 278

Define periodicity?

Back 278

A repeating trend in properties of theelements across each period of the periodic table

Front 279

Define a permanent dipole?

Back 279

A small charge difference that does not change across a bond with a slightly positive and sightly negative partial charge on the bonded atoms: the result of the bonded atoms having different electronegativities

Front 280

Define permanant dipole-dipole interaction?

Back 280

An attractive force between permanent dipoiles in neighboring polar molecules

Front 281

Define a polar (molecule)?

Back 281

With delta + and delta - at different ends of the molecule

Front 282

Define a polar covalent bond?

Back 282

A bond with a permanent dipole, having delta + and delta - partical charges on the bonded atoms

Front 283

Define a polar molecule?

Back 283

A molecule with an overall dipole, having taken into account any dipoles across bonds and the shape of the molecule

Front 284

Define a polyatomic ion?

Back 284

An ion containing more than one atom

Front 285

Define proton number?

Back 285

The number of protons in the nucleus of an atom, also known as the atomic number

Front 286

Define the retention time?

Back 286

In gas chromotography, the time for a component to pass from the column inlet to the detector

Front 287

Define a reversible reaction?

Back 287

A reaction that takes place in both the forward and reverse directions

Front 288

Define a shell?

Back 288

A group of atomic orbitals with the same principle quantum number 'n' also known as the main energy level

Front 289

Define the shielding effect?

Back 289

The repulsion between electrons to different inner shells. Shielding reduces the net attractive force between the positive nucelus on the outer shell electrons

Front 290

Define a simple molecular lattice?

Back 290

A three dimensional structure of molecules, bonded together by weak intermolecular forces

Front 291

Define the stationary phase?

Back 291

The phase that does not move in chromotography

Front 292

Define a sub-shell?

Back 292

A group of orbitals of the same type within a shell

Front 293

Define a transition element?

Back 293

A d-block element which forms an ion with an incomplete d-sub shell

Front 294

Describe the strength of hydrogen bonds relative to other intermolecular forces?

Back 294

It is the strongest type of intermolecule attractions

Front 295

What shows a hydrogen bond?

Back 295

A dashed line

Front 296

Why is ice less dense than the liquid water?

Back 296

1. Hydrogen bonds hold water molecules apart in an open lattice sturcture

2. The water molecules in ice are further apart than in water

3. Solid ice is less dense than liquid water and so floats

Front 297

What does ice form on the surface of water?

What does this do?

Back 297

It forms an insultaing layer on water, preventing the water from freezing solid to preserve fish and Aqautic life

Front 298

How many hydrogen bonds can each water molecule form?

Why?

Back 298

They can form four hydrogen bonds

Because there are two lone pairs on the oxygen and two hydrogen atoms

Front 299

What shape does water form?

What is the bond angle?

Back 299

An open tetrahedral lattice full of holes.

180 degrees

Front 300

What makes ice less dense that water?

Back 300

The tetrahedral shape it forms has holes in the sturcture, making the density of ice less than water on freezing.

When melting, the ice lattaice collapses and the molecules move closer, so liquid water is denser than solid ice

Front 301

Describe why water has a relatively high melting and boiling point in comparision to a substance with just hydrogen bonds?

Back 301

1. Hydrogen bonds are stronger than Lodon forces

2. A large quanitity of energy is needed to break the hydrogen bonds, so water has a much higher melting and boiling point than just london forces

Front 302

Describe hydrogen bonds when water is heated?

Back 302

When the ice lattice breaks, the rigid arrangement of hydrogen bonds in the ice is broken. Wehn water boils, the hydrogen bonds break compleelty

Front 303

Describe the properties of water without hydrogen bonds?

Back 303

1. Boiling point of -75 degrees

2. Exist as a gas at room temperature and pressure

3. Little liquid water in most places on Earth

4. Life wouldn't exisit as we know it

Front 304

For ions placed in the mass sepctrometer with a +1 charge what is m/z equal to?

Back 304

The relative isotopic mass

Front 305

What is relative atomic mass?

Back 305

The weighted mean mass of an atom of an element relative to 1/12th of the mass of an atom of carbon-12

Front 306

What does the weighted mean mass of an atom take into account?

Back 306

1. The percentage abundance of each isotope

2. The relative isotopic mass of each isotope

Front 307

Why is there a loss of a fraction of a mass of protons, neutrons and electrons?

Back 307

Because of the strong nucelur forces holding them together

Front 308

Define relative isotopic mass?

Back 308

It is the mass of an isotope relative to 1/12th of the mass of an atom of carbon-12

Front 309

State which two elements from the first twenty elements of the modern periodic table are not arranged in order of increasing atomic mass?

Back 309

Potassium and Argon

Front 310

Why is it uncessacary to refer to carbon as either diamond or graphite when ionised?

Back 310

Diamond and graphite form gaseous atoms of carbonwhen they are ionised

Front 311

Describe what is meant by the term ionic lattice in terms of the type and arrangement of particles present?

Back 311

Repeating pattern of oppositely charged ions

Front 312

Why, is CH2Cl2 polar if Cl is very electronegative?

Back 312

The dipoles do not cancel out because the molecule is non-symmetrical

Front 313

What forces are present in NH3?

Back 313

Hydrogen bonding and london forces

Front 314

Give to annomolus properties of ice?

Back 314

1. Density

2. High melting point

Front 315

Describe why ice has a high melting point?

Back 315

Hydrogen bonds are relatively strong and more energy is needed to overcome hydrogen bonding

Front 316

Describe what particles carry the charge in a molten metal?

Back 316

Delocalised electrons NOT ions

Front 317

Electrons in the outer shells of elements with a smaller radius experiance...

Back 317

Greater nucelar attraction

Front 318

State the element in Period 3 that has the highest melting point and explain why?

Back 318

Silicon

Because it is a metalloid that forms a giant covalent lattice. These bonds need lots of energy to be broken and therefore has a higher melting and boiling point that the simple molecules and metals

Front 319

Draw the trend in boiling points across group 3?

Back 319

Front 320

Describe what might cause the relative atomic mass of a sample be different to the relative atomic mass given in the periodic table?

Back 320

There are other isotopes present or some isotopes absent meaning there is different abundances of isotopes in the sample giving it a different atomic mass

Front 321

In a mass spectormter garph produced for magnesium containing 24^magnesium and 26^magnesium, there is a peak at 12, 24 and 26. Why is there a peak at 12?

Back 321

Because 2+ ions have been formed of 24^magnesium

Front 322

Describe the difference of the atomic radius of 124^Te compared to 130^Te?

Back 322

It is the same because both isotopes have the same number of protons so the same nuclear charge and they also have the same number of electrons

Front 323

Describe the difference of the atomic radius of 24^Mg and 26^Mg?

Back 323

They have the same atomic radius because both isotopes have the same number of protons and therefore the same nuclear charge and they both have the same number of electrons

Front 324

Describe how the gaseous atoms of rubidium are ionised in a mass spectrometer?

Back 324

They are passed by an electron gun which fires high speed and energy electrons at the rubidium atoms, knocking off electrons

Front 325

Describe the electrons that come out of an electron gun in a mass spectrometer?

Back 325

They are high speed and energy

Front 326

What is the name of the revlevant part of the mass epctrometer where the abundance of an isotope is determined?

Back 326

Detector/ Detector plate

Front 327

Describe how the abundance of an isotope in a sample of rubidium is determine after hitting the detection plate?

Back 327

The ions produce a charge, the size of the electrical signal produced is an indicator of the relative abundance of that isotope

Front 328

Althought phosphine molecules (PH3) contain hydrogen atoms, there is no hydrogen bonding between phosphine molecules. Suggest why?

Back 328

Because the phosphorus and hydrogen do not have a great enough electronegativity difference as phosphorus is not as electronegative as Oxygen, nitrogen and fluroine

Front 329

Describe why metals are malleable?

Back 329

Because the layers of ions in them can slide over each other

Front 330

Titanisum can be hammered into objects with different shapes that have similar strengths, suggest why these objects have similar strengths?

Back 330

Because the strong metallic bonding is reformed and so there is the same bond strength

Front 331

BCl3 can be reduced by using hydrogen to form pure boron and HCL. Apart from changing the reaction conditions, suggest one way a company producing pure boron could increase its profits from this reaction?

Back 331

By selling the HCl

Front 332

What is the mass number?

Back 332

The number of protons and neutrons in the nucelus of an atom of an element

Front 333

In a mass spectrometer, the relative abundance of each isotope is proportional to the current generated by that isotope at the detector, explain how the current is generated?

Back 333

Electrons are transferred from the detector plate to the positively charged ion causing a current to flow

Front 334

What type of structure is carbon found as?

What is it not?

Back 334

A giant molecular structure

A giant covalent lattice

Front 335

Suggest why the melting point of sodium iodide is lower than the nelting point of sodium bromide?

Back 335

Because iodine has more electrons so a greater atomic radius, because it is biger it has less of an attraction to the sodium ion