Question

why the valancy of phosphorus is 3,5 while other have only one valancy

Answer 1

HEYA!!!

IT IS SO BCOZ THE IONIZATION ENERGY OF PHOSPHORUS IS TOO MUCH SO IT CAN EASILY LOOSE 5 ELECTRONS.

#KEVIN

HOPE IT HELPS YOU ☺

Answer 2

because it's atomic number is15
its electronic configuration is 2,8,5
it can take 3 electron more for complete it's ocated . so it's valency is 3or5