The true statement concerning the atomic nucleus is:

It contains protons, neutrons, and electrons.

It takes up most of the volume of the atom.

It contains most of the mass of the atom.

It is made up of electrons only.

SH

1. It contains protons, neutrons and electrons which is a true statement for atomic nucleus.

We can also determine number of valence electrons through atomic number by its electronic configuration. (K, L, M ... Shells)