Question

-In the figure above, how many unpaired electrons does phosphorus have in its valence shell?
A) 15 
B) 2 
C) 3 
D) 7 
E) 5

Accepted Answer

Phosphorus has 5 electrons in its valence shell (in the 3p and 3s orbitals), with an electronic configuration of [Ne] 3s^2 3p^3. Out of these, 3 electrons in the 3p orbital are unpaired, making the correct answer 3.