The atomic number is always equal to the total number of which is also equal to the total number of

Protons; electrons.

Explanation:

An atom can be defined as the smallest unit comprising of matter that forms all chemical elements. Thus, atoms are basically the building blocks of matters and as such defines the structure of a chemical element.

Generally, these atoms are typically made up of three distinct particles and these are protons, neutrons and electrons. All the physical properties of a mineral result from the mineral's internal arrangement of atoms.

The atomic number is always equal to the total number of protons, which is also equal to the total number of electrons. Protons are the positively charged particles that make up an atom while electrons can be defined as subatomic particles that are negatively charged and as such has a magnitude of -1.

A chemical element is denoted by

Where;

X is the symbol of the element.

A is the atomic mass or number of nucleons.

Z is the atomic number or number of protons.

Therefore, the number of neutrons = A - Z