Which among the following lanthanoids has smallest atomic size?

Which among the following lanthanoids has smallest atomic size?
  1. $\operatorname{Pr}$
  2. $\mathrm{Ce}$
  3. $\mathrm{Sm}$
  4. $\mathrm{Pm}$

Solution

Atomic size decreases across the series from left to right. $\mathrm{Ce}>\mathrm{Pr}>\mathrm{Pm}>\mathrm{Sm}$

Asked in: MHT CET 2020 (13 Oct Shift 2)

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