Ionic compounds are composed of positively charged ions (cations) and negatively charged ions (anions). Cations are formed when metal atoms lose electrons, while anions are formed when non-metal atoms gain electrons.

The most common metals that form ionic compounds are the alkali metals (Group 1) and the alkaline earth metals (Group 2). These metals are highly reactive and easily lose electrons.

The most common non-metals that form ionic compounds are the halogens (Group 17) and the chalcogens (Group 16). These non-metals are also highly reactive and easily gain electrons.

Examples of ionic compounds

Here are some examples of ionic compounds:

- Sodium chloride (NaCl) is composed of sodium ions (Na+) and chloride ions (Cl-).

- Potassium iodide (KI) is composed of potassium ions (K+) and iodide ions (I-).

- Calcium oxide (CaO) is composed of calcium ions (Ca2+) and oxide ions (O2-).

- Magnesium sulfate (MgSO4) is composed of magnesium ions (Mg2+) and sulfate ions (SO42-).

Ionic compounds are essential for many biological processes. For example, sodium and potassium ions are involved in the regulation of fluid balance and nerve impulses. Calcium ions are involved in the formation of bones and teeth. Magnesium ions are involved in the synthesis of proteins and nucleic acids.