How do valence electrons affect the types of bonds an atom can form?

Valence electrons are the fundamental particles in the outermost region of an atom that determine how it interacts with other atoms to form chemical bonds. Because they are more weakly attracted to the nucleus than inner electrons, they can be shared or transferred during bonding.1

The number of valence electrons an atom possesses dictates the type of bond it typically forms:

• Ionic Bonds: Atoms with few valence electrons (typically metals) tend to lose them to nonmetals, forming positively charged ions. The resulting electrostatic attraction between these oppositely charged ions creates an ionic bond.23
• Covalent Bonds: When two nonmetals interact, they often share pairs of valence electrons to complete their octets, resulting in a covalent bond.23
• Metallic Bonds: Metal atoms bond to one another by releasing their valence electrons, which allows the electrons to move freely and conduct electricity.12

The distinction between these bond types is often viewed as a continuum based on the electronegativity of the atoms involved, which influences how strongly they attract shared valence electrons.4