What are the three sub-atomic particles of an atom?

a) relative mass
b) location
c) charge
-of each sub atomic particle?

Atoms contain an equal number of ____ and _____, so carry no overall _____.

atomic number = ...

mass number = ...

How do you work out the number of neutrons in an atom?

Lead has an atomic number of 82, and a mass number of 207.

Work out the number of:
a) protons
b) electrons
c) neutrons