The atomic mass of an element M is 39, and the number of neutrons is 20. What would be the electronic configuration of its ion M²�
a) 1s² 2s² 2pā¶ 3s² 3pā¶
b) 1s² 2s² 2pā¶ 3s² 3pāµ
c) 1s² 2s² 2pā¶ 3s² 3pā“
d) 1s² 2s² 2pⶠ3s² 3p³