What is the difference between a molecule and an ion?

Key Concepts

Molecule

A molecule is a group of two or more atoms bonded together by covalent bonds. These atoms can be of the same element, as in O2, or different elements, as in H2O. Molecules are electrically neutral, meaning they have no overall charge, and they represent the smallest fundamental unit of a chemical compound that retains its chemical properties.

Ion

An ion is an atom or molecule that has gained or lost one or more electrons, resulting in a net electrical charge. Ions can be positively charged (cations) or negatively charged (anions). For example, Na+ is a cation formed when sodium loses an electron, while Cl- is an anion formed when chlorine gains an electron. Ions play a crucial role in chemical reactions and electrical conductivity.

Chemical Bonding

Chemical bonding refers to the forces that hold atoms together in molecules and ions. In molecules, atoms are typically held together by covalent bonds, where they share electrons. In contrast, ions are held together by ionic bonds, which occur between oppositely charged ions. Understanding these bonding types is essential for distinguishing between molecules and ions and their respective properties.