Which of the following primarily determines an element's chemical reactivity?

• A. The melting point
• B. The atomic mass
• C. The number of valence electrons
• D. The number of neutrons

Answer: (C)

Verified step by step guidance

1. Understand that chemical reactivity of an element depends on how easily it can gain, lose, or share electrons to form chemical bonds.
2. Recall that electrons in an atom are arranged in shells, and the outermost shell electrons are called valence electrons.
3. Recognize that valence electrons determine how an element interacts with other elements because they participate in chemical bonding.
4. Note that properties like melting point and atomic mass do not directly influence chemical reactivity, as they relate to physical characteristics or total mass, not bonding behavior.
5. Conclude that the number of valence electrons primarily determines an element's chemical reactivity.