Question

5. Consider the 2p 3p excited state valence configuration of Be. (a) Calculate all allowed atomic terms arising from this configuration. [3 marks] (b) Calculate the degeneracy of the lowest energy term. [4 marks]

Answer 1

of Ber f 5. The excited Stal valence Canfuti Caleulatiod ofall allbaed ctomic terms anising frmy thie Canfirotio) Spin Spin Ceupling ST Saia Leuliplicity Cas) Smax 2 (as one ompine ineach 2pand St Onbit onlt Caphg Commepoalinghal Lmax tls 2- 1 D P 1-13 0 Potoric onbita) Thees all passible teie tem arheing Spincodot Couplig ) fors 3p L2 Tmar 2t123 Jain 2-1 1 Hence, Passible lavels fm 3p,

Jmax 2t0 2- L>2 Imas Jnin 2 Jmin 2-032 Possibe level arice termy fers 3p LL Jmax Itl 2 P Imin& 1-12 3 Jmax L Imin fers 3s Leo Iman Jmin 7 LO JnaK Jmin 20Iso SO Hence, all the posil term Spmdso tha exeltud dlechrenic Cenecad 2p spt aib and calcubtino of the degenenmoy of the ledst ene Amcny 3D has loout ereng

Hoc for 3ptmy has hei hihst Spin mutiphic colh highest value of L:2 Rx2t1-5. of the Sterto 2LtI Degaras and tenm Symbed SPisthe loast Or lovel amising form 2p em Enaroo Foro less than halffilled Contioeoration JL- CPeand stat) Degenanacy of the vel23tl2.1+I hence 3.