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Question
Q465) In the ground state, an element has 13 electrons in its M-shell. The element is ... [ EAMCET 2001]




SOLUTION

K shell = 1s
L shell = 2s, 2p
M shell = 3s, 3p and 3d
Now according to According to Hund's rule,
1s2, 2s2, 2p6, 3s2, 3p6,4s1, 3d5
Total number of electrons = 24
Thus atomic number = 24, Chromium
Answer: (b)