Question

The radius of La3+ (Atomic number of La = 57) is 1.06Å. Which one of the following given values will be closest to the radius of Lu3+ (Atomic number of Lu = 71) ?

• A. 1.60Å
• B. 1.40Å
• C. 1.06Å
• D. 0.85Å

Answer 1

Answer: (D)

0.85Å

Answer 2

Due to lanthanide contraction there occurs net decrease in size. Only one 0.85Å is smaller one. So radius of $L u _ { 71 } ^ { 3 + }$ will be closest to 0.85Å.