Valence electron

In chemistry, valence electrons are the electrons contained in the valence shell (the outermost electron level) of an atom, and which are likely to participate in a chemical reaction through bonding with other atoms, molecules, or ions.

Related Topics:
Chemistry - Electron - Valence shell - Atom - Bonding - Atoms - Molecules - Ions

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The number of valence electrons in an atom determines the chemical properties of that element; therefore, elements with the same number of valence electrons have very similar chemical properties. Valence electrons are also shared between atoms or ions to form chemical bonds. The bonds between atoms are called covalent bonds, which connect atoms together to form molecules. The bonds between ions are called ionic bonds, which connect positive ions (cations) and negative ions (anions) together to form ionic compounds (also called formula units). If an atom loses one or more valence electrons, it becomes a cation, or an ion with a positive charge. If an atom gains one or more electrons, it becomes an anion, or an ion with a negative charge.

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See chemical bonding.

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