Topic 2 (Bonding,Structure And Properties Of Matter)

Question 1

What are ions

Answer 1

Ions are charged particles. When metals form ions they lose electrons from their outer shell to form positive ions. When non metals form ions they gain electrons into their outer shell to form negative ions.

Question 2

What shows how ionic bonds are formed

Answer 2

Dot and cross diagrams, have each element in square brackets and draw the gained electron with a cross or dot from the atom it was lost from

Question 3

What structure do ionic compounds have

Answer 3

Regular lattice arrangement and there are very strong electrostatic forces of attraction betweeen oppositely charged ions in all directions on the lattice

Question 4

What are 4 properties similar in all ionic compounds

Answer 4

•High melting and boiling points due to many bonds between ions
•When they are solid the ions are held in place so the compounds can not conduct electricity
•When they melt, the ions are free to move and carry charge so they then can conduct electricity
•Some ionic compounds dissolve easily in water, the ions separate and are free to move and carry charge

Question 5

What shows how covalent bonds are formed

Answer 5

Dot and cross diagrams, electrons drawn in overlap represent the shared electrons between the two elements

Question 6

Substances that are covalently bonded usually have what structure

Answer 6

Simple molecular

Question 7

Properties of simple molecular substances include:

Answer 7

•Strong covalent bonds between atoms in molecule
•Weak intermolecular forces of attraction between molecules
•Low MP and BP as only the intermolecular forces need to be broken not the covalent bonds
•Most simple molecular substances are gas or liquid at room temperature
•They don’t conduct electricity as they are not charged and therefore have no free electrons or ions

Question 8

What are polymers

Answer 8

Polymers are long chains of small units linked together to form a large molecule

Question 9

How are atoms in polymers joined together

Answer 9

Strong covalent bonds

Question 10

What are simple molecular substances

Answer 10

Molecules containing few atoms joined by covalent bonds

Question 11

The intermolecular forces between polymer molecules are larger than simple molecular, what does this tell you about the BP and MP of polymers

Answer 11

The BP and MP of polymers will be higher than simple molecular substances, polymers will normally be solid at room temperature however the intermolecular orcas are still not as strong as covalent or ionic bonds so they still have lower MP and BP than giant molecular or ionic compounds

Question 12

What is a giant covalent structure

Answer 12

A macromolecule, in giant covalent structures all the atoms are bonded to each other by strong covalent bonds, this means they have very high melting points and boiling points in order to break the covalent bonds. They do not conduct electricity except for graphite.

Question 13

What are the three main examples of giant covalent structures

Answer 13

•Diamond
•Graphite
•Silicon Dioxide

Question 14

What is the structure of diamond

Answer 14

Each carbon atom forms four covalent bonds in a very rigid giant covalent structure

Question 15

What is the structure of graphite

Answer 15

Each carbon atom forms three covalent bonds to create layers of hexagons. Each carbon atom also has one delocalised electron

Question 16

What is the structure of silicon dioxide

Answer 16

Sometimes called silica, this is what sand is made of. Each grain of sand is one giant structure of silicon and oxygen

Question 17

Properties of diamond are

Answer 17

•It is very hard due to the four covalent bonds
•High melting point as it takes so much energy to break the four covalent bonds
•It doesn’t conduct electricity because it has free ions or electrons

Question 18

What is an allotrope

Answer 18

Allotropes are just different structural forms of the same element in the same physical state e.g they’re all solids.
Diamond, graphite,graphene and fullerenes are all allotropes of carbon

Question 19

Properties of graphite

Answer 19

•In graphite each carbon atom only forms three covalent bonds creating sheets of carbon atoms arranged in hexagons
•There aren’t any covalent bonds between the layers they’re only held together weakly so they’re free to move over each other. This makes graphite an soft and slippery, ideal for a lubricating material
•Graphite has a high melting point as it requires a lot of energy to break covalent bonds
•Only 3/4 of carbons outer electrons are being used in bonds so one is free to move and carry charge, therefore graphite can conduct electricity

Question 20

What is one sheet of graphite called

Answer 20

Graphene

Question 21

Properties of graphene

Answer 21

•A sheet of carbon atoms joined together in a hexagon
•Sheet is just one atom thick making it a two dimensional substance
•The network of covalent bonds makes it very strong however being so small it is also extremely light so it can be added to composite materials to improve their strength without adding much weight
•Like graphite one electron is free to move and carry charge, so graphene can conduct electricity

Question 22

What are fullerenes

Answer 22

Fullerenes are molecules of carbon shaped like closed tubes or hollow balls. They’re mainly made up of carbon atoms arranged in hexagons but can also contain pentagons and heptagons.

Question 23

What do spherical fullerenes do

Answer 23

Fullerenes that are spherical such as the buckminsterfullerene can be used to cage other molecules, the fullerene structure forms around another atom or molecule which is then trapped inside. This could be used to deliver a drug into the body. Aswell as this fullerenes have a large surface area so they can help to create great industrial catalysts as individual catalyst molecules can be attached to the fullerenes. Finally they also make great lubricants as they can roll over each other.

Question 24

What do fullerenes that are tube shaped do

Answer 24

Fullerenes can form nanotubes, tiny carbon cylinders. The ratio of length to diameter of nanotubes is extremely high they can conduct both electricity and thermal energy. They also have tensile strength (do not break when stretched). Nanotubes are used in nanotechnology, electronics or by strengthening materials without adding much weight e.g tennis racket frames

Question 25

Metallic bonding occurs within metals, what is it

Answer 25

Metallic bonding is the strong electrostatic force between the positive ions and the shared negative electrons between metal atoms. The strong forces of attraction hold the atoms together in a regular structure and are known as metallic bonding.

Question 26

What are harder, pure metals or alloys

Answer 26

Alloys, as metals form a regular structure they are often malleable where as mixing elements together means the layers are still extremely strong but in an irregular pattern and can not slide over one another.

Question 27

What are the three states of matter

Answer 27

Solid, Liquid and Gas

Question 28

Properties of a solid

Answer 28

•Strong forces of attraction between particles which holds them closed together in fixed positions to form a very regular lattice arrangement
•The particles don’t move so solid keep a definite shape and volume
•The particles vibrate in there fixed positions when heated, the hotter the solid becomes, the more they vibrate so solids expand slightly when heated

Question 29

Properties of liquids

Answer 29

•Weak forces of attraction between the particles. They’re randomly arranged and free to move past each other, but
they tend to stick closely together.
•Have a definite volume but don’t keep a definite shape and will flow to fill the bottom of a container
•The particles are constantly moving with random motion.The hotter the liquid gets, the faster they move.
This causes liquids to expand slightly when heated.

Question 30

Properties of gases

Answer 30

•Very weak forces of attraction between particles, they’re free to move and stay far apart
•Don’t keep a definite shape or volume and will always fill any container
•The hotter a gas gets the faster the particles move causing the gas to expand or their pressure increases

Question 31

Solid to Liquid

Answer 31

Melting

Question 32

Liquid to Gas

Answer 32

Boiling

Question 33

Gas to Liquid

Answer 33

Condensing

Question 34

Liquid to Solid

Answer 34

Freezing

Question 35

What are nano particles and what are they used for

Answer 35

Nano particles are extremely small particles with a diameter between 1nm and 100nm (1x10^-9m and 1x10^-7m)
They can be used to make new catalysts, deliver drugs into the body like fullerenes, tiny electric circuits, deodorant and much more

Question 36

Surface area:Volume Ratio Equation

Answer 36

Surface Area:Volume

Surface Area/
Volume