Mass number (A)

Definition

The mass number (A) is the total number of protons and neutrons in an atom's nucleus. It gives the atomic mass unit (amu) of the atom, which is crucial for understanding the atom's overall stability and reactivity.

Related terms

Proton:

A positively charged particle located within an atom's nucleus that contributes to the atom's overall positive charge.

Neutron:

A neutral particle found in the nucleus of an atom that adds to its mass but does not affect its electrical charge.

Atomic Number (Z): The number of protons in an atom's nucleus, which determines the element's identity and its position on the periodic table