Which term describes electrons in the outermost energy level that influence chemical behavior?

• A. Core electrons
• B. Valence electrons
• C. Protons
• D. Neutrons

Answer: (B)

The term describes electrons in the outermost energy level that influence chemical behavior because these are the electrons that participate in bonding and reactions. These outermost electrons, called valence electrons, are the ones that atoms can gain, lose, or share to form bonds, which is why they largely determine how reactive an element is and what kinds of compounds it tends to form. For example, sodium has one valence electron and readily loses it to achieve a noble-gas configuration, while chlorine tends to gain one to complete its outer shell. Noble gases have full valence shells, making them mostly inert. In contrast, core electrons sit closer to the nucleus and mainly serve to shield the nucleus; they don’t participate directly in bonding and thus don’t strongly influence chemical behavior. Protons and neutrons reside in the nucleus and affect mass and identity, not the bonding behavior we experience in chemistry.