A molecule or atom with a net electrical charge is an ion. Conventional wisdom holds that the charge of an electron is negative, which is the exact opposite of the charge of a proton, which is typically held to be positive. An ion's total number of electrons is not equal to its total number of protons, so its net charge is not zero. An anion, on the other hand, is a negatively charged ion that has more electrons than protons. A cation is a positively charged ion that has fewer electrons than protons. Cations and anions are attracted to one another and readily form ionic compounds because opposite electric charges are pulled toward one another by electrostatic force. Atomic or monatomic ions are ions with just one atom, whereas molecular or polyatomic ions have two or more atoms. Ion pairs are created by spontaneous molecule collisions when physical ionization occurs in a gas or liquid. Each generated pair consists of a free electron and a positive ion. Ions can also be produced by other means, like passing a direct current through a conducting solution and ionizing an anode, or by chemical interactions like when a salt dissolves in liquids.

The word ion comes from the Greek neuter present participle ienai, which means to go. An anion is a substance that moves upward, while a cation is one that moves downward. Ions move toward the electrode with the opposite charge, which is why they are called that. After William, an English polymath, suggested it Michael an English physicist and chemist, coined the term for the then-unknown species that moves through an aqueous medium from one electrode to the next. Although Faraday had no idea what these species were made of, he did know that, at one electrode, metals dissolved into and entered a solution, and at the other, new metal emerged from the solution; that a substance of some kind has flowed in a current through the solution. Matter is moved from one location to another by this. Whewell also invented the terms anode and cathode, as well as anion and cation, which refer to ions that are drawn to the respective electrodes, in correspondence with Faraday. Svante Arrhenius won the Nobel Prize in Chemistry in 1903 for his explanation of why dissolved solid crystalline salts dissociate into paired charged particles in his 1884 dissertation. The salt dissociates into Faraday's ions when forming a solution, according to Arrhenius, who proposed that ions formed even in the absence of an electric current. In their gas-like state, ions are highly reactive and quickly interact with ions of opposite charge to form neutral molecules or ionic salts. Solvated ions, which are more stable for reasons involving a combination of energy and entropy changes as the ions move away from each other to interact with the liquid, are also produced in the liquid or solid state when salts interact with solvents (like water). At low temperatures, these stabilized species are more prevalent in the environment. The ions in seawater, which come from dissolved salts, are a common example. Ions, as charged objects, repel like charges and are attracted to electric charges that are opposite to them (positive to negative and vice versa). A magnetic field can alter their trajectories when they move. Atoms and molecules with any electrons are sized by electrons because of their smaller mass and larger space-filling properties as matter waves. Because the ion's size is determined by its electron cloud, anions (negatively charged ions) are larger than the parent molecule or atom because the excess electrons repel one another and increase the ion's physical size. Because the electron cloud is smaller, cations are smaller than their parent atom or molecule. A single proton, much smaller than the parent hydrogen atom, makes up one type of cation hydrogen cation that lacks electrons. The net electric charge of an ion is indicated by the symbols ion and cation. An anion is an ion that has a net negative charge because it has more electrons than protons. The negative charge is indicated by the minus sign Anion. The exact opposite occurs with a cation: It has a net positive charge because it has fewer electrons than protons, which is why it is called a cation.

With Regards,
Joseph Kent
Journal Manager
Journal of Der Chemica Sinica