4.4 The Atomic Nucleus Is Made of Protons and Neutrons

Atomic Mass

This video lesson focuses on the concept of atomic mass, which is the average mass of all the isotopes of an element. Listen carefully. Duration: 7:54.

Subatomic Particles Organized

How the three basic subatomic particles are organized in the atom is discussed. Various definitions that help us describe the atom are also presented. Duration: 10:46.