Statement TypeDirection (Q. Nos. 24and 25) This section is based on St...
Both statements I and II are correct. Statement II correctly explains the statement I.
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Statement TypeDirection (Q. Nos. 24and 25) This section is based on St...
Statement Type Explanation
The given question belongs to the class 12 category and requires an explanation of the correctness and relation between two statements.
Statement I : The second and third rows of transition elements resemble each other much more than they resemble the first row.
This statement suggests that the second and third rows of transition elements have more similarities between each other compared to the first row.
Statement II : Due to lanthanide contraction, the atomic radii of the second and the third-row transition elements.
This statement suggests that the atomic radii of the second and third-row transition elements are affected by the phenomenon called lanthanide contraction.
Explanation
To understand the correctness and relation between the two statements, let's analyze each statement individually:
Statement I states that the second and third rows of transition elements resemble each other much more than they resemble the first row. This statement is correct because the second and third rows of transition elements have similar properties due to the presence of partially filled d-orbitals. The elements in these rows have similar electron configurations and exhibit similar chemical behavior.
Statement II states that due to lanthanide contraction, the atomic radii of the second and third-row transition elements. This statement is also correct. Lanthanide contraction refers to the decrease in atomic and ionic radii of elements in the 6th and 7th periods of the periodic table. This contraction occurs because the addition of inner f-orbitals does not effectively shield the increasing nuclear charge, leading to a decrease in atomic size. As a result, the atomic radii of the second and third-row transition elements are smaller compared to the first row.
Relation between Statement I and Statement II
Statement II provides an explanation for Statement I. The similarity between the second and third rows of transition elements can be attributed to the lanthanide contraction. The decrease in atomic radii due to lanthanide contraction leads to an increase in effective nuclear charge, resulting in similar chemical behavior and properties among the elements in the second and third rows.
Conclusion
Based on the above analysis, both Statement I and Statement II are correct, and Statement II provides the correct explanation for Statement I. Therefore, the correct answer is option 'A' - Both Statement I and Statement II are correct, and Statement II is the correct explanation of Statement I.