What are the components of an atom and what are their properties?

An atoms is composed of a central NUCLEUS, with ELECTRONS occupying shells, moving around the nucleus.

The nucleus is composed of PROTONS and NEUTRONS.

The PROTON has a relative mass of 1 and a charge of +1.

The NEUTRON has a relative mass of 1 and a charge of 0.

The PROTON has a very small relative mass and a charge of -1.