What is a cation?

A cation is defined as a positively charged ion. This occurs when an atom loses one or more electrons, resulting in a surplus of protons compared to electrons. The loss of electrons, which are negatively charged, allows the overall charge of the ion to become positive. Cations are typically formed from metals, which tend to lose electrons easily due to their relatively low ionization energies.

In the context of the other options, a neutral ion would have no charge, which does not align with the definition of a cation. A negative ion, known as an anion, is formed when an atom gains electrons, therefore having a negative charge. Lastly, a compound ion refers to a group of atoms that are covalently bonded together and have an overall charge, such as sulfate (SO₄²⁻) or ammonium (NH₄⁺), but this does not specifically define a cation, which is singular and positively charged.