Ions are positively or negatively charged particles that form as a result of an atom losing an electron or gaining a proton. Ions form when metals react with nonmetals and exchange protons or electrons. In an ionized particle, the number of protons is not equal to the number of electrons.
On the periodic table, alkali metals are found in Group one. When alkali metals bond with nonmetals, they form a compound with a single positive charge. Halogens, found in Group seven of the periodic table, after reacting with metals, have a single negative charge.
There are a number of different types of ions. Monatomic ions are defined as a single, charged atom. Monatomic ions are formed as a result of gaining or losing electrons from the atom's valence shield. An atom with a positive charge is a cation, whereas an atom with a negative charge is an anion. While ions are most commonly formed as a result of chemical reactions, they can also be formed as a result or radiation bombardment.
Plasma is a form of matter along with gases, solids and liquids. Plasma is unique in that it is composed of ionized gaseous particles, making it the most common form of matter in the universe.