What are valence electrons?

• A. Electrons in the outermost shell
• B. Electrons in the innermost shell
• C. Protons in the nucleus
• D. Neutrons in the nucleus

Answer: (A)

Valence electrons are the electrons in the outermost electron shell of an atom. They’re the ones available to participate in chemical bonding with other atoms, and they largely determine an element’s reactivity and how it forms bonds. That’s why describing valence electrons as those in the outermost shell is the best fit. Electrons in inner shells are more tightly bound and less involved in bonding, while protons and neutrons reside in the nucleus, not in electron shells.