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Explain about the causes of lanthanide contraction. |
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Answer» Solution :(1) As we MOVE from one element to another in 4f series ( Ce to Lu) the nuclear charge INCREASES by one unit and an additional electron is added into the same inner 4f sub-shell. (ii) 4f sub-shell have a diffused shapes and therefore the shielding effect of 4f electrons are relatively POOR. Hence, with increase of nuclear charge, the valence shell is pulled slightly towards nucleus. (iii) As a result, the effective nuclear charge EXPERIENCED by the 4f elelctorns increases and the size of `Ln^(3+)` ions decreases. |
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