The dand fblock elements - Result Question 35
####35. The electronic configuration of $Cu$ (atomic number 29) is
[1991]
(a) $1 s^{2}, 2 s^{2} 2 p^{6}, 3 s^{2} 3 p^{6}, 4 s^{2} 3 d^{9}$
(b) $1 s^{2}, 2 s^{2} 2 p^{6}, 3 s^{2} 3 p^{6} 3 d^{10}, 4 s^{1}$
(c) $1 s^{2}, 2 s^{2} 2 p^{6}, 3 p^{2} 3 p^{6}, 4 s^{2} 4 p^{6}, 5 s^{2} 5 p^{1}$
(d) $1 s^{2}, 2 s^{2} 2 p^{6}, 3 s^{2} 3 p^{6}, 4 s^{2} 4 p^{6} 3 d^{3}$
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Solution:
- (b) Electronic configuration of $Cu(29)$ is $1 s^{2}$ $2 s^{2} 2 p^{6} 3 s^{2} 3 p^{6} 4 s^{1} 3 d^{10}$ and not $1 s^{2}, 2 s^{2} 2 p^{6} 3 s^{2}$ $3 p^{6} 4 s^{2}, 3 d^{9}$ due to extra stability of fully filled orbitals.
