Valence determines which property of an atom?

• A. Bonding capacity
• B. Atomic weight
• C. Reactivity with oxygen
• D. Color

Answer: (A)

Valence is the combining power of an atom—the number of bonds it tends to form with other atoms. This directly defines its bonding capacity: atoms with valence 1 form one bond, valence 2 form two bonds, valence 4 can form four bonds, and so on. The other properties aren’t set by valence alone: atomic weight depends on the total number of protons and neutrons in the nucleus, color comes from specific electronic transitions and energy gaps, and reactivity with oxygen involves the overall electron arrangement and other factors beyond just valence. So valence most directly determines how many bonds an atom can form—the bonding capacity.