Question

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 :

• A. A and B only
• B. C and D only
• C. B and D only
• D. A and E only

Answer 1

Answer: (C)

B and D only

Answer 2

1. 62?Sm:4f66s2
2. 64?Gd:4f75d16s2
3. 63?Eu:4f76s2
4. 65?Tb:4f96s2
5. 1?Pm:4f56s2
So , the correct option is (C) : B and D only