Bonding And Structure

Front 1

Good conductor, Soft, very high melting point

-Describe the bonding and structure in Graphite

-Explain, in terms of bonding and structure, the properties of graphites shown above

Back 1

Main: giant covalent lattice in layers

-Good conductor - because it has mobile electrons ORde-localised electrons.

-High melting point - because strong covalentbonds have to be broken

Soft- weak intermolecular forces between the layers

Front 2

Explain what is meant by a covalent bond.

Back 2

a shared pair of electrons

Front 3

Dot and cross- NH3

Back 3

-

Front 4

Name the shape of the ammonia molecule and explanation.

Back 4

Name: Pyramidal or (trigonal) pyramid

Explanation:

-There are 3 bonded pairs and 1 lone pair

-Lone pairs repel more than bonded pairs

Front 5

Complete the electron configuration of the cl(-) ion.

Back 5

1s2 2s2 2p6 3s2 3p6

Front 6

Dot and Cross of NH4+

Back 6

Front 7

State the shape of, and bond angle in, an NH4= ion.

Back 7

Shape: tetrahedral

Bond Angle: 109.5Oc

Front 8

Ammonium chloride solid don't conducts however dissolved in water it conducts

Explain why.

Back 8

-ions cannot move in a solid

-ions are mobile in solution

Front 9

Explain, with diagram, what is meant by the term metallic bonding.

Back 9

-metallic bond as (electrostatic) attraction between theelectrons and the positive ions

Front 10

State what is meant by the term ionic bond

Back 10

(electrostatic) attraction between oppositely charged ions

Front 11

Compare and explain the electrical conductivities of sodium and sodium oxide in the solid andliquid states

Back 11

- sodium is a (good) conductor because it has mobile delocalised electrons

-sodium oxide does not conduct as a solid

ions cannot move in a solid

-sodium oxide conducts when it is a liquid

ions are mobile when liquid

Front 12

State what is meant by the term atomic number.

Back 12

number of protons (in the nucleus)

Front 13

Complete the full electron configuration for a titanium atom.

Back 13

(1s2) 2s2 2p6 3s2 3p6 3d2 4s2

Front 14

Explain, with the aid of a diagram, the intermolecular forces in H2O that lead to the relatively high boiling point of H2O.

Back 14

relatively strong hydrogen bonds between O and H.

Front 15

Suggest why H2S has a much lower boiling point than H2O.

Back 15

-no hydrogen bonding

-weaker intermolecular forces

Front 16

What is meant by the term ionic bonding?

Back 16

-(Electrostatic) attraction between oppositely chargedions.

Front 17

Draw a "dot-and-cross" diagram of a molecule of f20

Back 17

Draw:

Front 18

Predict the bond angle in an f20 molecule.

Explain your answer.

Back 18

Predicted bond angle 104–105Oc.

There are 2 bonded pairs and 2 lone pairs

Lone pairs repel more than bonded pairs

Front 19

Describe and explin one anomalous property of water which results from hydrogen bonding

Back 19

-Liquid H2O is denser than solid

-In solid state H2O molecules are held apart byhydrogen bonds OR ice has an open lattice

-H2O has a relatively high boiling point OR meltingpoint

-hydrogen bonds are relatively strong

Front 20

Describe the structure and bonding shown by these elements.

Back 20

-Mg has a giant structure

-Mg has metallic bonding OR description of metallic bonding as positive ions and delocalised electrons

-(There is electrostatic attraction between) positiveions and electrons

-Cl has a simple molecular OR simple covalent(lattice)

-temporary dipole–temporary dipole

Front 21

Describe, with the aid of a labelled diagram, the structure and bonding in lithium and explain why lithium has a high boiling point.

Back 21

-The attraction between + ions and e– is strong OR metallic bonding is strong

Front 22

Explain why fluorine has a low boiling point

Back 22

- F2 has induced dipoles

-London dispersion force

- which are weak

Front 23

Explain why lithium fluoride conducts electricity when molten but not when solid.

Back 23

-Ions cannot move in a solid

-Ions are mobile when molten

Front 24

Name the shape of, and state the bond angles in, a BF3 molecules.

Explain why BF3 has this shape.

Back 24

Shape: trigonal planar

Bond angle: 120°

Explanation:Pairs of electrons repel (one another equally)

Boron has 3 bonded pairs (and 0 lone pairs)

Front 25

Nitrogen can also form a fluoride, NF3, which has a permanent dipole.

Explain why NF3 has a permanent dipole.

Back 25

-F is more electronegative than N

-Dipoles do not cancelORNF3 is pyramidal (in words) / asymmetrical

Front 26

What is meant by the term ionic bonding?

Back 26

-(Electrostatic) attraction between oppositely chargedions

Front 27

Explain why a solution of copper(II) nitrate conducts electricty

Back 27

Ions are mobile

Front 28

What is meant by the term electronegativity

Back 28

The ability of an atom to attract electrons

Front 29

State the shape of a molecule of SF6

Back 29

Octahedral

Front 30

Explain, in terms of inter-molecular forces present, why IcL has a higher boiling point than Cl2

Back 30

Exp1:ICl has permanent dipole (–dipole) (interactions)
-Cl2 has (only) London dispersion
-Forces are stronger in ICl and more energy is needed to overcome forces in icL
Exp2:-ICl has more electrons
-Stronger london dispersion forces in ICl(than in Cl2) and therefore More energy is needed to overcome london dispersion forces in ICl

Front 31

Explain why there is a difference in the melting points of K, KBr and H20

Back 31

-In KBr, electrostatic attraction between oppositely charged ions.KBr has ionic bonding AND

K has attraction between positive ions and electrons

-In K, electrostatic attraction between positive ions/cation.K has metallic bonding AND K has attraction between positive ions and electrons

-In H2O, hydrogen bonding Between molecule

Order of strength of forces: KBr > K > H2O

Front 32

Why can ammonium sulfate be described as a salt?

Back 32

H+ ions in sulfuric acid are replaced with ammonia ions.

Front 33

state what is meant by the term covalent bond

Back 33

A shared pair of electrons

Front 34

Explain how chemists can predict shape of a simple covalent molecule from the number electron pairs surrounding the central atom.

Back 34

-Pairs of electrons surrounding a central atom repel

-The shape is determined by the number of bond pairs

-the number of lone pairs of electrons

Front 35

Predict the O-B-O and B-O-H bond angles in a molecule of H3BO3.

Back 35

O-B-O=120o

B-O-H= 104.5o

Front 36

Give an example of a simple covalent molecules which has all bond angle of 90o

Back 36

SF6 OR sulfur hexafluoride

Front 37

Chlorine is more reactive than bromine.

Explain why?

Back 37

-Chlorine will gain an electron more easily than bromine

-(An atom of) chlorine is smaller (than bromine)

-(Outermost shell of) chlorine is less shielded (than bromine)

-Nuclear attraction (on the electron to be gained) by chlorine is greater (than bromine)

Front 38

Explain why there is a difference in the boiling points of HCl and F2?

Back 38

-F2 has temporary OR instantaneous dipole(–dipole)attraction OR interactions

-HCl has permanent dipole(–dipole) attractions ORinteractions

-intermolecular force in HCl is stronger than that in F2

-more energy is required to break stronger (intermolecular)forces

Front 39

WHat are the main intermolecular forces present in NH3 and PH3

Back 39

-hydrogen bonding

-Permanent dipole(–dipole interactions)

Front 40

Suggest why PH3 has a lower boiling point than NH3.

Back 40

the intermolecular forces are weaker in PH3

Front 41

A covalent bond is a shared pair of electrons.

What is a dative covalent bond?

Back 41

Both electrons have been donated by one atom

Front 42

Draw dot and cross of H3NBF3

Back 42

Front 43

Group 2 element react with halogens.

Describe and explain the trend in reactivity of Group 2 elements with chlorine as the group is descended

Back 43

-Reactivity increases (down the group)

-Atomic radius increases

- There is more shielding

-Nuclear attraction (to electron) decreases

-Increased nuclear charge is outweighed by increased shielding/distance

-Ionisation energy decreases

Front 44

To identify iodine ion in chlorine iodine. What do you add?

What what would happen?

Back 44

-Dilute silver nitrate

-Yellow precipitate

Front 45

Explain the trend across Period 2.

Back 45

-greater nuclear charge

- electrons experience the same shielding

- Atomic radius decreases

-Greater nuclear attraction (on outermost electrons

Front 46

Solid carbon exists in two forms, diamond and graphite.

Explain why it is unnecessary to refer to carbon as either diamond or graphite.

Back 46

Diamond and graphite form gaseous atoms of carbonwhen they are ionised

Front 47

Complete table

Back 47

Front 48

Back 48

-(N in) NH3 has three bonding pairs and one lone pair ofelectrons

- (N in) H3NBF3 has four bonding pairs (and no lone pairs)of electronsORLone pair on N now becomes bonding pair

- Lone pair of electrons repels more than bonding pairs