Atomic Mass Number

Definition

The atomic mass number of an atom is the total number of protons and neutrons in its nucleus.

Related terms

Proton: A subatomic particle with a positive charge that resides within the nucleus of an atom.

Neutron: A subatomic particle without any electric charge that resides within the nucleus of an atom.

Nucleus:

The central part of an atom where protons and neutrons are located.