Phosphorus has _____ valence electrons.?

Question

A. 15
B. 2
C. 3
D. 5

Answer 1

The first thing you need to know to answer this question is the atomic number for Phosphorus, which is 15. That is the number of protons (and thus electrons) it has.

The valence shell is the outermost shell of an atom in its uncombined state, which contains the electrons most likely to account for the nature of any reactions involving the atom and of the bonding interactions it has with other atoms. Electrons in the valence shell are referred to as valence electrons.

Possible Number of Electrons in shells 1-6:
Shell 1 can have 2
Shell 2 can have 8
Shell 3 can have 18
Shell 4 can have 32
Shell 5 can have 50

The shells fill in order (electrons go to the lowest energy state). So for phosphorus, the first shell is full (2), the second shell is full (8). So 10 of the 15 electrons are accounted for. There is room for up to 18 electrons in shell 3 but there are only 5 electrons left. Therefore phosphorus has 5 valence electrons.

Answer 2

D .5

Answer 3

Anthing in group 5A will have 5 electrons..
N, P, As, Sb, Bi..