Calculation of Atoms

We have two main or basic calculations we must know. They are:

The Atomic Number or Proton Number

This is written as a subscription on the lower left of the chemical symbol.

It also shows the position of the chemical element arrangement. Examples are 20Ca, 10Ne, 18Ar. the atoms are Ca, Ne and their atomic or proton numbers are 20, 10 and 18 respectively.

The atomic number or proton number is denoted by the letter Z.

Mass Number or Nucleon Number

This is the sum of the protons and neutrons number in the nucleus of an atom. It is denoted by the letter A. it is written as a superscript on the upper left of the chemical symbol.