Ion
An ion is an atom, an atomic group, or a subatomic particle with a single amount of electric charge. The simplest ions are electrons, protons, and alpha particles. A negatively charged ion, which has more electrons in the electron shell than the amount of protons in the nucleus, is known as anion, as it is attracted to the anode; while a positively charged ion, which has less electrons than protons, is known as cation, as it is attracted to the cathode. An anion poliatom containing oxygen is sometimes known as oxianion. The ions are marked just as neutral and molecular atoms behave electrified except for the presence of a 'superscript' which indicates the amount of electric charge and the number of electrons more than one. For example: H +, SO42-. Another way to show this charge is as follows: SO4-2.