C2

The number of neutrons + the number of protons

The number of protons in an element

( alsot he number of electrons)

Particle Charge Mass

Proton +1 1

Neutron 0 1

Electron -1 1/2000

Atomic mass - atomic number of an element

When two or more elements are chemically bonded together though a chemical reaction and are difficult to separate

Different atomic forms of the same element with the same number of protons (atomic number) but a different number of neutrons (atomic mass)

Occurs between a metal and a non-metal

Atoms lose of gain electrons to form ions with a charge that are strongly attracted to each other as they have opposite charges

They only have one or two electrons in their outer shell so they are in group 1 or 2

They try to lose those one or two electrons to gain a full outer shell of electrons

The gain + charges

They have 6 or 7 electrons in their outer shell so they re in group 6 or 7

The try to gain 1 or 2 electrons to gain a full outer shell

They gain - charges

It forms a giant ionic lattice

They have a regular arrangement

There are very strong electrostatic forces of attraction between oppositely charged ions

They have high melting and boiling points ( lots of strong bonds require a lot of energy to break)

When melted or dissolved they can conduct electricity as their ions are free to move through the substance and carry the current

Two non-metals share electrons in their outer shells to each gain a full outer shell

These atoms form very strong covalent bonds to form simple molecules

They have low melting and boiling points as the intermolecular forces between molecules are very weak and easy to break

Mainly gases or liquids at room temperature

Don't conduct electricity -no charged particles

All the atoms are bonded together by strong covalent bonds

They have high melting and boiling points

Don't conduct electricity

Each carbon atom is bonded to four other carbon atoms

This forms a rigid structure

Therefore it doesn't conduct electricity

Each carbon atom is only bonded to 3 other carbon atoms

Therefore there is one free carbon atom which has a delocalised electron allowing it to conduct heat and electricity

It exists in hexagonal layers which slide over each other as there are weak intermolecular forces

Positive ions in a giant structure with a sea of delocalised negative free electrons

There are strong metallic bonds between the positive ion and the negative electron

The electrons allow it to conduct electricity and hold the regular structure so layers can slide

They are a mixture of two or more metals

They have different sized atoms distorting the layers so they can't slide

Materials which behave differently depending on conditions such as temperature

For example nitinol can be used in dental braces and when cooled can be remoulded and then when reheated it remembers this shape and tries to return to this shape pulling your teeth

Particles less than 100 Nm across

They can be used in sensors and makeup as they have a high surface area to volume ratio

Molecules of carbon that are shaped in tubes in hexagonal rings

They an be used for reinforcements as the covalent bonds are very strong

A polymer made of individual polymer chains held together by weak intermolecular forces

They don't have cross links so can be melted and remoulded easily

A polymer made of polymer chains joined by cross links giving strong intermolecular forces

They can't be melted or remoulded

You can change the starting materials

Conditions

LD polythene - hot temperature + high pressure

HD Polythene - low temperature + low pressure + catalyst

The relative mass of an atom compared with the mass of one atom of carbon-12

Same as the mass number

All of the atomic masses in a compound added together

The relative formula mass of a substance in grams

= Mass / RFM

Ar X No of atoms