Question

The reactivity of an atom is due to the number and arrangement of _______ in the outer energy level.

Answer 1

Answer:

electron

Explanation:

Answer 2

The reactivity of an atom is due to the number and arrangement of Electrons (b) in the outer energy level.

Electrons "bond" they're the ones that react to create other elements.

Examples: Salt (NaCl) Carbon Dioxide (CO2)

And so on, and so forth. Thus, your answer....B.