Answer:
5
Explanation:
Valence electrons refers to the number of electrons in the outermost orbital of an atom that determines it's ability to bond with others.
Majority of the time, the valence of an atom is the same as the group number in which he element belongs to.
The electrons per shell is; 2, 8, 5
Phosphorus with the symbol P, belongs to group 5.
5 is the answer.
