The atomic nucleus is the small, dense region consisting of protons and neutrons at the center of an atom, discovered in 1911 by Ernest Rutherford based on the 1909 Geiger–Marsden gold foil experiment. ... Almost all of the mass of an atom is located in the nucleus, with a very small contribution from the electron cloud.

What is the atomic nucleus called?

Atomic nuclei consist of protons and neutrons. The number of protons is the atomic number (Z), and the sum of the number of protons (Z) and neutrons (N) is the mass number (A). The particles composing the nuclei are called “nucleons.”

What is an atomic nucleus answer?

The atomic nucleus is the central area of the atom. It is composed of two kinds of subatomic particles: protons and neutrons. The number of protons and neutrons in the atom define what type of atom or element it is. An element is a bunch of atoms that all have the same type of atomic structure.