BioCoach Activity

Concept 2: Valence and Covalent Bonding

Each element has a characteristic valence that determines the number of covalent bonds it can form.

The ability of an atom to combine with other atoms depends on the number of electrons in the outer shells of the atoms. Some elements, the so-called noble gases, have complete outer shells and do not share electrons. Many elements will share electrons with other elements, such that each element completes its outer electron shell capacity.

A shared electron pair is called a covalent bond. The number of covalent bonds that each element can form is called its valence.

Spheres (6) with valence positions

The CHNOPS atoms are shown above. Each valence position is represented by a stick protruding from the atom.