Very tiny:

 A penny contains about 2 × 10²²

Negatively charged particles located around electron clouds.  They orbit around the nucleus.

The small and dense positively charge center of the atom that takes up most of the atom's mass.  It is so dense that if it was the size of a graepe it would be greater than 9,000,000 tons.

Positively charged particles in nucleus of the atom.

Particle in the center of the atom that has no charge.

The number of protons in the nucleus of an atom

An atom that has the same number of protons (or the same atomic number) as other atoms of the same element do, but that has a different number of neutrons (and therefore a different atomic mass).

The sum of the numbers of protons and neutrons in the nucleus of an atom.

The mass of an atom expressed in atomic mass units

The mass of an atom expressed in atomic mass units