Question

the reactivity of an element is based on its _______. a protons b electrons _____ electrons are the most important electrons to an atom. a outer b inner _______ refers to how reactive a substance is with oxygen. a reduction b combustibility

Explanation:

1. The reactivity of an element is mainly determined by its electrons, especially the valence - electrons which participate in chemical reactions. Protons determine the element's identity but not reactivity directly.
2. Outer electrons, also known as valence electrons, are involved in bonding and chemical reactions, making them the most important for an atom's chemical behavior. Inner electrons are more stable and less involved in reactions.
3. Combustibility refers to how reactive a substance is with oxygen, often resulting in burning. Reduction is a chemical process involving the gain of electrons and is not about reactivity with oxygen in the same context.

Answer:

1. B. electrons
2. A. Outer
3. B. Combustibility