Chemistry IGCSE (1)

-atoms are made up of protons neutrons and electrons.

- the nucleus of an atom contains protons and neutrons

- the electrons are found at large distances from the nuceus.

- proton charge- +1 relative mass- 1

- Electron change : -1 relative mass- 1/1836

- Neutron charge: 0 relative mass- 1

Atomic number= number of protons in an atom 

Mass number= proton number + number of neutrons

Neutron number= mass number - proton/atomic number

Number of neutrons in an atom can vary slightly eg:

there are three kinds of carbon: carbon-12 carbon-13 carbon-14.

They all have SAME number of PROTONS (atomic number) but the number of NEUTRONS vary!

these different forms of the same elements are called ISOTOPES