Question

What is correct order of size in each pair given below ?

$N{b}^{3+}$ and $T{a}^{3+}$

• A. $N{b}^{3+}$ =$T{a}^{3+}$
• B. $N{b}^{3+}$ < $T{a}^{3+}$
• C. $N{b}^{3+}$ > $T{a}^{3+}$
• D. None of these

Answer 1

The correct option is A $N{b}^{3+}$ =$T{a}^{3+}$

Option (A) is correct.

$N{b}^{3+}$ and $T{a}^{3+}$ have same order of size (ionic radii) as a consequence of lanthanoid contraction. They belong to group 5 (VB).