NCERT Class XII Chemistry
Chapter - The d- and f-Block Elements
Questions with Solutions
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Question : 28
Total: 49
What are inner transition elements? Decide which of the following atomic numbers are the atomic numbers of the inner transition element :
29, 59, 74, 95, 102, 104.
29, 59, 74, 95, 102, 104.
Solution:
Lanthanoids and actinoids are called inner transition elementsbecause inner f-orbitals are progressively filled and the last electron goesto anti-penultimate f orbital.
Elements with atomic number 59, 95, 102 are inner transition metalsbecause theybelong to lanthanoids and actinoids.
P r ( 59 ) 1 s 2 2 s 2 2 p 6 3 s 2 3 p 6 4 s 2 3 d 10 4 p 6 5 s 2 4 d 10 5 p 6 6 s 2 4 f 3 A m ( 95 ) 1 s 2 2 s 2 2 p 6 3 s 2 3 p 6 4 s 2 3 d 10 4 p 6 5 s 2 4 d 10 5 p 6 6 s 2 4 f 14 5 d 10 6 p 6 7 s 2 5 f 7 N o ( 102 ) 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 4 f 14 5 s 2 5 p 6 5 d 10 5 f 14 6 s 2 6 p 6 7 s 2
Elements with atomic number 59, 95, 102 are inner transition metalsbecause theybelong to lanthanoids and actinoids.
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