Question

Which one of the following statements about lanthanides is false?

• A. Lanthanides are separated from one another by ion exchange method
• B. The ionic radii of trivalent lanthanides steadily increases with increase in atomic number
• C. All lanthanides are highly dense metals
• D. Most typical oxidation state of lanthanides is +3

Answer 1

The correct option is B The ionic radii of trivalent lanthanides steadily increases with increase in atomic number

In lanthanides (At no. of elements 58 to 71) the electronic configuration of three outermost shelts are $(n-2{)}^{f-14},(n-1)s^2{p}^6{d}^{10to1}n{s}^2$.
So most typical oxidation state of lanthanides is +3.
All lanthanides are highly dense metals and Lanthanides are separated from one another by ion exchange method.
The ionic radii of trivalent lanthanides steadily decreases with increase in atomic number due to lanthanide contraction.