key term - Nucleus

Definition

The nucleus is at the center of an atom consisting mainly of protons and neutrons. It carries most of an atom's mass but occupies only a tiny space compared to the total size of the atom.

Related terms

Atomic Number:

The number of protons in the nucleus of an atom, which determines the chemical properties of an element and its place in the periodic table.

Nucleons: Protons and neutrons collectively are known as nucleons.

Radioactive Decay:

A process by which an unstable atomic nucleus loses energy by radiation. It can involve the release of alpha or beta particles from the nucleus.