Chemistry - Structure + Bonding

Front 1

Ionic compound

Back 1

A giant, regular structure of ions. They are held together in a lattice by the strong forces of electrostatic attraction between oppositely charged ions. These forces extend in all directions.

Front 2

Ionic compounds do not have ________ and so do not have ____________ forces, like ______ ________ ________. There are also no _____, as ions are not the same as these.

Back 2

1. molecules

2. intermolecular

3. atoms

Front 3

Covalent bonds + structures (simple)

Back 3

When atoms share electron pairs, they form strong covalent bonds. Covalently bonded substances containing simple molecules include H2, Cl2, O2, HCl, H2O, NH3 and CH4.

Front 4

Covalent structures (giant) - examples

Back 4

Silicon dioxide, diamond, graphite

Front 5

Describe the atomic structure of a metal.

Back 5

Metals consist of a giant structure of atoms arranged in a regular pattern. The outer shell electrons are delocalised and so free to move around, forming a sea of delocalised electrons and positive metal ions. These attract eachother, and so stay together.

Front 6

1) Group 1 elements 2) Group 7 elements

Back 6

1) Alkali metals all react to form ionic compounds where the metal has a charge of 1+

2) Halogens all react with alkalis to form ionic compounds where the halide ion has a charge of 1-

Front 7

Compounds

Back 7

Substances in which the atoms of two or more elements have been chemically combined.

Front 8

Chemical bonding

Back 8

Either involves sharing or transferring electrons in the highest shells in order to achieve the electronic structure of a noble gas (noble gas configuration)

Front 9

Ionic bonding

Back 9

Formed when atoms form chemical bonds by transferring electrons. Metals lose electrons and are oxidised, becoming positively charged cations. Non-metals do the opposite, and are reduced, becoming anions. Ions have noble gas configuration.

Front 10

Boiling and melting points of 1) substances consisting of simple molecules 2) ionic compounds 3) giant covalent compounds

Back 10

1) low - only the weak intermolecular forces holding the molecules together are broken.

2) high - electrostatic forces are strong

3) very high - covalent bonds are strong.

Front 11

How is a substance melted or boiled?

Back 11

The heat gives them kinetic energy, causing them to vibrate faster. This energy is passed along the substance and the object heats up.

Front 12

1) Conductivity of ionic compounds

2) Conductivity of metals

3) Conductivity of substances containing simple molecules

Back 12

1. They conduct in molten form or when in solution, because the ions spread out and become free to move and carry the current.

2. They do conduct, as the free electrons in their structures are able to move

3. They do not conduct, as they have no overall electrical charge or free charged particles.

Front 13

What is another name for the very large molecules in a giant covalent structure?

Back 13

Macromolecule

Front 14

What are diamond and graphite in relation to carbon? (same element, different number of atoms/atoms are bonded differently)

Back 14

Allotropes

Front 15

Structure of a giant covalent substance

Back 15

They are linked with strong covalent bonds. There are no molecules. The covalent bonds must be broken on heating, giving them very high melting and boiling points.

Front 16

Diamond contains carbons bonded to _ other carbons. Graphite has _. This leaves free ________, making it conductive. It also has _____ connected by _________ _________, making it slippery.

Back 16

1. 4

2. 3

3. electrons

4. layers

5. intermolecular forces

Front 17

What do the layers do in metals?

Back 17

They can slide over each other, making metals malleable.

Front 18

1) Alloys 2) shape memory alloys

Back 18

1) Alloys are made of two different metals. The different sized atoms distupt the layers, making it harder for them to slide over eachother, making alloys harder than pure metals.

2) Shape memory alloys return to their original shape after being deformed

Front 19

Properties of polymers

Back 19

Depend on materials + conditions under which they were made. E.g. low density and high density poly(ethene) are produced using different catalysts in different reaction conditions.

Front 20

Fullerenes

Back 20

Carbon can form fullerene tubes (carbon atoms bonded in sheets of hexagons like graphite, curved into tubes) or spheres with different numbers of C atoms.

Front 21

Nanoscience

Back 21

Structures that are 1-100nm (1 millionth of a mm). They show different properties alone to when they are in bulk and have high surface area to volume ratios.

Front 22

What is the ion 1) carbonate 2) sulphate 3) hydroxide 4) nitrate 5) oxide?

Back 22

1. CO32-

2. SO42-

3. OH-

4. NO3-

5. O2-

Front 23

Uses for nanoparticles

Back 23

-catalysts

-computers

-strong, light building materials

-cosmetics

-highly selective sensors

-coatings

Front 24

Structure of 1) thermosetting plastics 2) thermosoftening plastics

Back 24

1) The polymer chains are cross-linked with covalent bonds.

2) Chains only have weak intermmolecular forces between them

Front 25

How are polymers made?

Back 25

-Alkanes are fractionally distilled.

-They are made into alkenes via cracking

-Alkenes are made into polymers under high pressure and temperatures with a catalyst

-The double bond opens out and creates a polymer chain with other monomers.

Front 26

How does the structure of thermosetting plastics relate to their properties?

Back 26

The cross-links make the structure inflexible and rigid, as there is no way the covalent bonds can rotate when attached in that way. Strong covalent bonds require a lot of energy to break, so they have high melting and boiling points.

Front 27

How does the structure of thermosoftening plastics relate to their properties?

Back 27

The weak intermolecular forces can allow rotation of the covalent bonds, making them flexible when heated. They do not require as much energy to break and so they have low melting and boiling points.

Front 28

What is meant by 1) thermosetting 2) thermosoftening? Give an example of their uses.

Back 28

1. They will only char and can not be re-melted - milk bottles

2. They will always melt when heated and can be remoulded - plastic bags

Front 29

What is the difference between the structures of HDPE and LDPE?

Back 29

HDPE is straight - but LDPE has branches that stops the polymer chains from getting very close together, giving it a low density.

Front 30

How can LDPE be 1) produced 2) converted into HDPE?

Back 30

1) Ethene under high pressure with a trace of oxygen.

2) Using a catalyst at 50 degrees celcius under lots of pressure.

Front 31

Solubility of 1) simple molecular structures 2) ionic structures 3) all others

Back 31

1) insoluble (usually)

2) soluble (usually)

3) insoluble

Front 32

Uses and properties of fullerenes, including nanotubes

Back 32

-caging potentially harmful drugs

-catalysts

-strong lightweight construction materials. -medicinal molecules need a specific shape that can be achieved by using fullerenes as a 'molecular scaffold' for 'molecular manufacturing'.

They are semi-conductors, very strong for their mass, have large surface area to volume ratios.

Front 33

What do many metals react with?

Back 33

Water, oxygen, acids

Front 34

Why does the upper energy level/outer shell contain electrons with the most energy?

Back 34

Overcoming the forces between the oppositely charged particles and moving further from the nucleus requires more energy.

Front 35

How can you tell if a new substance has been produced in a chemical reaction?

Back 35

It will have different properties, a reaction doing this may release/absorb energy and the reactants are not easily separated afterwards.

Front 36

Why does something become positively charged when it loses and electron?

Back 36

Because it means they have one more proton than neutron, meaning they have one more + charge than - charge.

Front 37

How do metals conduct electricity?

Back 37

The delocalised electrons in their structures all move at once when a potential difference is applied to carry the electrical charge.