What are the particles on the outer shell of an atom called? valence electrons orbiting protons neutrons nuclei

Electrons are the sub atomic particles of an atom which are on the outer rotating orbit and the outer shell contains the valence electrons.  

Option A

Explanation:

The valence electrons are those which determines the valency of an atom. This is determined by the number of electron required to fill up the outer shell.

The filling up of outer shell is essential in order to become a stable atom. Therefore the outer shell consists of the particle referred to as the valence electrons.