[Moss]

Hey

why is Sn^+2

when i look at the periodic table the outermost shell has 4, should it be -4 as the charge?

for example tin displaces copper metal from CuSO4 solution

Sn^+4 + CuSO4---> Cu + Sn(SO4)_4
thanks

[UG]

Well you see, this has to do with the electron configuration. Have you learned anything about the s, p, d and f orbitals and writing the electron configuration using these? e.g Na electron configuration can be written as 1s²2s²2p⁶3s¹... If you haven't learned this then it probably isn't worth explaining why tin forms Sn²⁺

[Moss]

yeah i remember learning that!

[UG]

Well the electron configuration of tin is [Kr]4d¹⁰5s²5p²
[Kr] = electron configuration of Krypton, I'm too lazy to write it 
Anyway, so the atom loses the two 5p electrons and forms a 2+ ion, Sn²⁺

[Ranadeep]

yeah ..and also .. Sn Exhibits Variable Oxidation States .. +2 and +4 where +2 is generally more stable and this is Explained by " Inert pair Effect " in some reaction we observe Sn with +4 : )