The atom having the valence shell configuration 3s2 3p3 would be: a. group 3a, period 5 b. group 5a, period 3 c. group 7a, period 4 d. group 3a, period 3

- B. Group 5A, period 3.

Explanations:- From the given electron configuration the element has 5 electrons in outer most shell. It tells us the element is present in group 5A.

Value of principal quantum number is three which is the number written in front of s and p in the electron configuration and it tells us about the period number. The number is 3 means element is present in period 3.

So, the right answer is, B. group 5A, period 3.

it means there are 3 atoms of oxygen

i think   the answer is c hope i'm right