List the steps involved in russell-saunders (l-s) coupling to obtain states arising from an electronic configuration. write out the formulae involved and explain the meaning of any symbols used. (10) given that the lowest energy transition of atomic magnesium ([ne]3s? ) involves the promotion of an electron from the 3s atomic orbital to the 3p orbital: (1) obtain the states arising for both configurations, (ne]3s2 and [ne]3s3p. [10 m (ii) order the states derived in part (i) from the lowest to highest energy. (5 md (ii) from your answer in part (ii), determine the lowest energy allowed absorption transition of magnesium. justify your answer.