Chemistry · Ch 9 — Elements of Group 13, 14 and 15
Electronic configuration of elements of groups 13, 14 and 15
Electronic configuration of elements of groups 13, 14 and 15
The general outer electronic configuration of group 13 elements is ns²np¹, of group 14 elements is ns²np², and of group 15 elements is ns²np³. In each case this configuration is 3 or 4 electrons short of the nearest noble gas, so none of these elements exists in nature as a free monoatomic species — instead they occur combined as compounds, or as polyatomic molecules such as N2, P4 and C60, or as extended polyatomic covalent arrays such as graphite and diamond. Down each group the outer ns²npˣ pattern stays the same, but the inner core changes: period-2 members (B, C, N) have only a [He] core; period-3 members (Al, Si, P) add a filled 3s3p shell; period-4 members (Ga, Ge, As) additionally carry a filled 3d¹⁰ subshell; and period-6 members (Tl, Pb, Bi) carry both a filled 4f¹⁴ and 5d¹⁰ subshell beneath their outer 6s²6pˣ electrons. These extra filled d and (for period 6) f subshells shield the nucleus poorly, and this poor shielding is exactly what caus …
Group 13 (boron family): B [He]2s²2p¹, Al [Ne]3s²3p¹, Ga [Ar]3d¹⁰4s²4p¹, In [Kr]4d¹⁰5s²5p¹, Tl [Xe]4f¹⁴5d¹⁰6s²6p¹. Group 14 (carbon family): C [He]2s²2p², Si [Ne]3s²3p², Ge [Ar]3d¹⁰4s²4p², Sn [Kr]4d¹⁰5s²5p², Pb [Xe]4f¹⁴5d¹⁰6s²6p². Group 15 (nitrogen family): N [He]2s²2p³, P [Ne]3s²3p³, As [Ar]3d¹⁰4s²4p³, Sb [Kr]4d¹⁰5s²5p³, Bi [Xe]4f¹⁴5d¹⁰6s²6p³. Note how the 4th- and 6th-period members each carry a filled inner d (and, for period 6, f) subshell that the 2nd- and 3rd-period members lack — this difference is what causes the …