Question

The correct order of ionic radii `Y^(3+)` , `La^(3+)` , `Eu^(3+)` and `Lu^(3+)` is `(AT. No : Y = 39, La = 57, Eu = 63, Lu = 71)`
A. `Lu^(3+) lt Eu^(3+) lt La^(3+) lt Y^(3+)`
B. `La^(3+) lt Eu^(3+) lt Lu^(3+) lt Y^(3+)`
C. `Y^(3+) lt La^(3+) lt Eu^(3+) lt Lu^(3+)`
D. `Y^(3+) lt Lu^(3+) lt Eu^(3+) lt La^(3+)`

Answer 1

Correct Answer - D
The correct order of the ionis radii
`Y^(3), La^(3+), Eu^(3+)` and `Lu^(3+), "is" Y^(3+) lt Lu^(3+) lt Eu^(3+) lt La^(3+)` because Eu and Lu are the members of lanthanide series (so they show lanthanide contraction and La is the representative element of all element of such series and `Y^(3+)` ion has lower radii as comparison to `La^(3+)` because it lies immediately above it in the periodic table.