Classification Of Elements And Periodicity In Properties Question 8
Question 8 - 31 January - Shift 2
Which of the following elements have half-filled f-orbitals in their ground state?
(Given : atomic number
$Sm=62 ; Eu=63 ; Tb=65 ; Gd=64, Pm=61$ ) A. $Sm$ B. $Eu$ C. $Tb$
D. Gd E. $Pm$
Choose the correct answer from the options given below:
(1) B and D only
(2) A and E only
(3) A and B only
(4) C and D only
Show Answer
Answer: (1)
Solution:
Formula: Classification of-the elements
-
$ _{62} Sm: 4 f^{6} 6 s^{2}$
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$ _{64} Gd: 4 f^{7} 5 d^{1} 6 s^{2}$
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$ _{63} Eu: 4 f^{7} 6 s^{2}$
-
$ _{65} Tb: 4 f^{9} 6 s^{2}$
-
$ _{61} Pm: 4 f^{5} 6 s^{2}$
