Which of the following represents the electronic configuration of an element with atomic number 17:
(1) 1s2, 2s2, 2p6, 3s1, 3p6
(2) 1s2, 2s2, 2p6, 3s2, 3p4, 4s1
(3) 1s2, 2s2, 2p6, 3s2, 3p5
(4) 1s2, 2s2, 2p6, 3s1, 3p4, 4s2
Ans: 1s2, 2s2, 2p6, 3s2, 3p5