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The electronic configurations of Eu (Atomic No. 63), Gd (Atomic No. 64) and Tb (Atomic No. 65) are medium
The d and f Block Elements
2016
chemistry
[ X e ] 4 f 7 6 s 2 , [ X e ] 4 f 8 6 s 2 a n d [ X e ] 4 f 8 5 d 1 6 s 2 [Xe]4f^7 6s^2, [Xe]4f^8 6s^2 and [Xe]4f^8 5d^1 6s^2 [ X e ] 4 f 7 6 s 2 , [ X e ] 4 f 8 6 s 2 an d [ X e ] 4 f 8 5 d 1 6 s 2
[ X e ] 4 f 6 5 d 1 6 s 2 , [ X e ] 4 f 7 5 d 1 6 s 2 a n d [ X e ] 4 f 9 6 s 2 [Xe]4f^6 5d^1 6s^2, [Xe]4f^7 5d^1 6s^2 and [Xe]4f^9 6s^2 [ X e ] 4 f 6 5 d 1 6 s 2 , [ X e ] 4 f 7 5 d 1 6 s 2 an d [ X e ] 4 f 9 6 s 2
[ X e ] 4 f 6 5 d 1 6 s 2 , [ X e ] 4 f 7 5 d 1 6 s 2 a n d [ X e ] 4 f 8 5 d 1 6 s 2 [Xe]4f^6 5d^1 6s^2, [Xe]4f^7 5d^1 6s^2 and [Xe]4f^8 5d^1 6s^2 [ X e ] 4 f 6 5 d 1 6 s 2 , [ X e ] 4 f 7 5 d 1 6 s 2 an d [ X e ] 4 f 8 5 d 1 6 s 2
[ X e ] 4 f 7 6 s 2 , [ X e ] 4 f 7 5 d 1 6 s 2 a n d [ X e ] 4 f 9 6 s 2 [Xe]4f^7 6s^2, [Xe]4f^7 5d^1 6s^2 and [Xe]4f^9 6s^2 [ X e ] 4 f 7 6 s 2 , [ X e ] 4 f 7 5 d 1 6 s 2 an d [ X e ] 4 f 9 6 s 2
Explanation To solve this problem, we need to determine the electronic configurations of europium (Eu), gadolinium (Gd), and terbium (Tb).
\newline The atomic numbers are given as follows:
\newline • Eu (Atomic No. 63)
\newline • Gd (Atomic No. 64)
\newline • Tb (Atomic No. 65)
\newline Let's analyze the electronic configurations step-by-step:
\newline
\newline 1. Europium (Eu, Atomic No. 63):
\newline
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• The configuration of xenon (Xe, Atomic No. 54) is:
[ X e ] = 1 s 2 2 s 2 2 p 6 3 s 2 3 p 6 3 d 10 4 s 2 4 p 6 4 d 10 5 s 2 5 p 6 [Xe] = 1s^2 2s^2 2p^6 3s^2 3p^6 3d^{10} 4s^2 4p^6 4d^{10} 5s^2 5p^6
\newline [ X e ] = 1 s 2 2 s 2 2 p 6 3 s 2 3 p 6 3 d 10 4 s 2 4 p 6 4 d 10 5 s 2 5 p 6 • After Xe, we fill the 4f and 6s orbitals:
• Eu has 9 more electrons to distribute:
4 f 7 6 s 2 4f^7 6s^2
\newline 4 f 7 6 s 2 • Therefore, the configuration is:
[ X e ] 4 f 7 6 s 2 [Xe]4f^7 6s^2
\newline
\newline [ X e ] 4 f 7 6 s 2 2. Gadolinium (Gd, Atomic No. 64):
• Following Eu, Gd has one more electron:
• The electron enters the 5d orbital to minimize energy:
4 f 7 5 d 1 6 s 2 4f^7 5d^1 6s^2
\newline 4 f 7 5 d 1 6 s 2 • Therefore, the configuration is:
[ X e ] 4 f 7 5 d 1 6 s 2 [Xe]4f^7 5d^1 6s^2
\newline
\newline [ X e ] 4 f 7 5 d 1 6 s 2 3. Terbium (Tb, Atomic No. 65):
• Following Gd, Tb has one more electron:
• The electron enters the 4f orbital:
4 f 9 6 s 2 4f^9 6s^2
\newline 4 f 9 6 s 2 • Therefore, the configuration is:
[ X e ] 4 f 9 6 s 2 [Xe]4f^9 6s^2
\newline
\newline [ X e ] 4 f 9 6 s 2 Analyzing the options:
• Option 1: Incorrect configuration for Gd and Tb.
• Option 2: Incorrect configuration for Eu and Tb.
• Option 3: Incorrect configuration for Eu and Tb.
• Option 4: Correct configurations for Eu, Gd, and Tb.
Therefore, the correct option is Option 4.