What is a negatively charged particle called?

A negatively charged particle within an atom is called an electron. Electrons were discovered in 1897 by a British scientist named J.J. Thomson.

All of the electrons found in an atom balance out the protons of the atom. Protons are the positively charged particles in the atom's nucleus. The electrons are found in clouds surrounding the nucleus and they move at a very rapid pace. Electrons play a large part in creating different chemical bonds. An electrovalent bond is created by transferring an electron from one atom to another. Covalent bonding takes place when two or more atoms share electrons in a cloud.