The valency of phosphorus is 3,5 how will I know which to use when??
Dear student
Regards
Phosphorous shows both the valencies 3 and 5.
Electronic configuration of Phosphorous
P: 1s 2s2 2p63s2 3p3
Phosphorous with valency 3:
With three unpaired electrons in three p orbitals, phosphorous shows valency 3, like in case of compound PCl3.
Phosphorous with valency 5:
In case of PCl5, one of 3s electron gets promoted to 3d orbital as follows:
P: 1s2 2s2 2p6 3s1 3p33d1
You can know which valency to use, depending on the compound and the substituents attached.Regards