Q: Given a scientific passage and an answer, generate a question for the given answer.
Passage: Some nonmetals are very reactive, whereas others are not reactive at all. It depends on the number of electrons in their outer energy level. Answer: reactivity
A:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
The number of electrons in the outer energy level determines what property of nonmetals?