Phosphorus Has an Atomic Number of 15, So What Is

Multiple Choice

Phosphorus has an atomic number of 15, so what is the distribution of its electrons?

A) The first, second, and third energy levels have 5 electrons each.
B) The first energy level has 2, the second has 8, and the third has 5.
C) The first energy level has 8 and the second has 7.
D) The first energy level has 2 and the second has 13.
E) The electron arrangement cannot be determined from the atomic number alone.