The correct order of ionic radii of \(Y^{3+}, La^{3+}, Eu^{3+}\) and \(Lu^{3+}\) is:
Answer & explanation
Correct answer: option 4
The correct answer is option 4. \(Y^{3+} < Lu^{3+} < Eu^{3+} < La^{3+}\)
The ionic radii of the lanthanide ions decrease as the atomic number increases. This is due to the lanthanide contraction, which is a decrease in the size of the lanthanide ions due to the increasing nuclear charge.
Yttrium is not a lanthanide element, but it has similar chemical properties. The ionic radius of Y3+ is slightly larger than the ionic radii of the lanthanide ions.
Therefore, the order of the ionic radii of \(Y^{3+}, La^{3+}, Eu^{3+},\) and \(Lu^{3+}\) is:\(Y^{3+} < Lu^{3+} < Eu^{3+} < La^{3+}\)