Chemistry · Periodic trends in properties of elements: atomic and ionic radii, ionization enthalpy, electron gain enthalpy, valence, oxidation states and chemical reactivity
Assertion The atomic radii of the elements of oxygen family are smaller than the
Assertion The atomic radii of the elements of oxygen family are smaller than the atomic radii of corresponding elements of the nitrogen family. Reason The members of oxygen family are all more electronegative and thus have lower value of nuclear charge than those of the nitrogen family.
- A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
- B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
- C. Assertion is correct but Reason is incorrect
- D. Assertion is incorrect but Reason is correct
Step-by-step solution
Atomic radii decrease across a period due to increased effective nuclear charge. Elements of Group 16 (oxygen family) have one more proton than corresponding Group 15 (nitrogen family) elements, so their atomic radii are smaller. The reason incorrectly states that oxygen family members have lower nuclear charge; in fact, they have higher nuclear charge. Therefore, assertion is correct but reason is incorrect.