Year: 2016
Topic: The d-and f-Block Elements
Time :
1.
The electronic configurations of Eu (Atomic no. 63), Gd (Atomic no. 64) and Tb (Atomic no. 65) are
(1). [Xe] 4f
6
5d
1
6s
2
, [Xe] 4f
7
5d
1
6s
2
and [Xe] 4f
9
6s
2
(2). [Xe] 4f
6
5d
1
6s
2
, [Xe] 4f
7
5d
1
6s
2
, and [Xe] 4f
8
5d
1
6s
2
(3). [Xe] 4f
7
6s
2, [Xe] 4f
7
5d
1
6s
2
and [Xe] 4f
9
6s
2
(4). [Xe] 4f
7
6s
2
, [Xe] 4f
5
6s
2
and [Xe] 4f
8
5d
1
6s
2