BITSAT2011ChemistryClassification of Elements and Periodicity in PropertiesActual
The correct order of radii is
Options
- AN < Be < B
- BF ⁻< O ²⁻< N ³⁻
- CNa < L ₁< K
- DFe ³⁺< Fe ²⁺< Fe ⁴⁺
Correct answer
B. F ⁻< O ²⁻< N ³⁻
Step-by-step solution
Effective nuclear charge (i,e. Z/e ratio) decreases from F ⁻ to N ³⁻ hence the radii follows the order: F ⁻< O ²⁻< N ³⁻ . Z / e for F ⁻=9 / 10=0.9, for O ²⁻=8 / 10=.8, for N ³⁻=0.7