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The +1oxidation state in group 13 and +2 oxidationstate in group 14 becomesmore and morestable with increasing atomic number. Explain |
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Answer» Solution :Theouter electronic configurationof GROUP 13 element is `ns^(2) NP^(1)` and hence their group oxidation state is `+3`. Both B and Al showan oxidationstate of `+3`. Howover , from GA to Tl.The elementhave either `d-` or `d-` andf-electronsbesidess- andp-electrons. Since d- and f-electronshave poor shieldingeffect,THEREFORE , they do not screen s-electronof the valencesheleffectively from the attraction of the nucleus. Consequently,two s-electrons of the valenceshell remain attractedby the nucleusand hence do notparticipat in bond formationwhile only the remaining one p-electron of the valenceshell participatesin bondformation.Further, as the number of d- or d- and f-electronincreasesdown the group, the inert pair effect becomes more nad more prominent. Consequently, the solubility of +3 oxidationstate decreaseswhile that of +1oxidation state increasesdown the group. The outer electronicconfiguationof group 14 element in `ns^(2) np^(2)` and hencetheir group oxidationstate is+4. Both C and Si show an oxidation state of +4. However, from Ge to Pb , the elements have eitherd- or both d- and f-electrons, in addition to s- and p-electrons. Due topoor shielding of s-electrons of the valenceshell bythese d- and f-electrons , the inertpair effectcomes into play. As a result, theelementsfrom Ge toPb showoxidationstates of +2 and +4 . Further , as the number ofd- or d- and f-electronsincreasesdown thegroup, the inert pair effect becomes more andmore perdominant. Consequently, the stabilityof +4 oxidationstate decreases while that of +2 oxidation stateincrease down thegroup from Ge to Pb. |
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