Explanation:
1) There are three sub atomic particles; protons, neutrons and electrons. Protons and Neutrons are found in the nucleus while electrons are found in orbitals outside the Nucleus.
2) No. This is not always the case. An example is sodium which has atomic mass of 23.
Atomic Mass = Neutrons + Protons
23 = Neutrons + 11
Neutrons = 23 - 11 = 12
In sodium there are 11 protons and 12 neutrons
