Question

Which of the following atomic numbers are the atomic numbers of the inner transition elements?
(A) Atomic number 29
(B) Atomic number 59
(C) Atomic number 74
(D) Atomic number 95
(E) Atomic number 102

• A. (C), (D) and (E)
• B. (A), (D) and (C)
• C. (B), (D) and (E)
• D. (A), (D) and (E)

Answer 1

Answer: (C)

Elements with atomic number $59,95,102$ are inner transition metals because they belong to lanthanoids and actinoids.
$Pr(59)1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{6}5s^{2}4d^{10}5p^{6}6s^{2}4f^3$
$Am(95)1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{6}5s^{2}4d^{10}$
$5p^{6}6s^{2}4f^{14}5d^{10}6p^{6}7s^{2}5f^7$
$No(102)1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^{10}4s^{2}4p^{6}4d^{10}4f^{14}$
$5s^{2}5p^{6}5d^{10}5f^{14}6s^{2}6p^{6}7s^2$