Question

Which electron configuration represents an
atom of chlorine in an excited state?
(1) 2–8–7 (3) 2–8–6–1
(2) 2–8–8 (4) 2–8–7–1

Answer 1

(4)2-8-7-1 The maximum number of electrons in the second two shells is 8, but since there is 7 in the third she'll and 1 in the fourth, that means that one electron was moved to the last shell, putting the atom in the excited state.