WHAT IS AN ATOM?
It's how electrons are arranged in an atom
This is the number of protons in an atom
Number of protons = Number of electrons
e.g Na has 11 protons, so it's atomic number is 11
how to represent atoms by displaying their atomic and mass numbers
Relative Atomic Mass (R.A.M)
How many times does the mass of 1/12 th the mass of carbon fit into one atom of that element