1) The radius of La3+ (Atomic number of La=57) is 1.06 Å. Which one of the following given values will be closest to the radius of Lu3+ (Atomic number of Lu = 71)? A) 1.40 Å B) 1.06Å C) 0.85 Å D) 1.60 Å Answer: Option CExplanation:$Ionic radii \propto \frac{1}{z}$ $Thus \frac{z_{2}}{z_{1}}\Rightarrow\frac{1.06}{(Ionic radii of Lu^{3+})} = \frac{71}{57}$ Ionic radii of Lu3+ = 0.85Å
