What is atomic number , mass number and atomic mass

Atomic Number

It is defined as the number of unit positive charges on the nucleus (nuclear charge) of the atom of that element. It is denoted by z. It is basically the number of protons and this number is also equal to the number of electrons in a neutral atom.

Atomic number = number of protons = number of electrons.

Mass Number

The sum of the protons and neutrons present in the nucleus of the atom is known as the mass number of the atom.

Atomic Mass

Atomic mass of an isotope = mass of neutrons + mass of protons.