One evening last summer, as I strolled along the promenade in Limbe, a small, scenic port town in southwestern Cameroon, I was stopped by a well-dressed young man who greeted me warmly and took me by the hand.
Phosphorus has 3 shells. The outer shell contains 5 electrons. The electronic configuration is :- <br /> 1s2, 2s2, 2p6, 3s2, 3p3.
1 The first shell can have one sub-shell (1s) while the second shell (L) can have two sub-shells (2s & 2p). 2  There can be three sub shells in third electron shell (M); 3s, 3p, 3d and four in fourth shell; 4s, 4p, 4d, 4f.3  After fourth shell, the number of sub shells in an atom remains same. The first shell can have one sub-shell (1s) while the second shell (L) can have two sub-shells (2s & 2p). 2  There can be three sub shells in third electron shell (M); 3s, 3p, 3d and four in fourth shell; 4s, 4p, 4d, 4f.