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Match List I with List II
Choose the correct answer from the options given below: |
A-II, B-IV, C-I, D-III A-IV, B-III, C-I, D-II A-II, B-I, C-III, D-IV A-IV, B-I, C-II, D-III |
A-II, B-I, C-III, D-IV |
The correct answer is 3. A-II, B-I, C-III, D-IV. The given elements belong to the lanthanide series. Lanthanides refers to 14 metallic elements present in f-block with atomic numbers ranging from 58-71. The general electronic configuration of lanthanides is \[4f^{1−14}5d^{0−1}6s^2\] The last electron always enters into the 4f orbital (Aufbau principle). All lanthanides show an oxidation state of \(+3\). It also shows an oxidation state of \(+2\) and \(+4\) in complexes, but \(+3\) is the most stable. During oxidation, electrons are removed from 6s (2 electrons) and \(4f\) orbital (1 electron). A big energy difference lies between \(6s\) and \(4f\) orbital. Being closer to the nucleus, 4f doesn’t lose electrons as easily.
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