Question

Which of the following explains why elements in column 17 (the halogens) are very reactive? A. Their atoms contain three energy levels.. . B. Their atoms need only one electron to complete their outer energy level.. . C. Their atoms have large masses.. . D. Their atoms contain the same number of protons as electrons..

Answer 1

I believe the correct response is B. Their atoms need one electron to complete their outer energy level.

Answer 2

The answer is B, as halogens will have a full octet after receiving another electron in their outer energy level.