Atoms are electrically neutral, with a positively charged nucleus that binds one or more electrons in motion around it. Small particles suspended in liquid move spontaneously in a random fashion. The motion is caused by unbalanced impacts of molecules on the particle. Brownian motion provided strong circumstantial evidence for the existence of molecules. A negatively charged beam that emanates from the cathode of a discharge tube.
Cathode rays are streams of electrons.
Compare with anode . The electrode at which reduction occurs. Compare with anion . A cation is a positively charged ion. Metals typically form cations.