NEETChemistryClassification of Elements and Periodicity in Properties
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): The atomic radius of oxygen is smaller than that of nitrogen. Reason (R): Effective nuclear charge increases from left to right across a period. In the light of the above statements, choose the most appropriate answer from the options given below:
Options
- ABoth (A) and (R) are correct and (R) is the correct explanation of (A)
- BBoth (A) and (R) are correct but (R) is not the correct explanation of (A)
- C(A) is correct but (R) is not correct
- D(A) is not correct but (R) is correct
Correct answer
A. Both (A) and (R) are correct and (R) is the correct explanation of (A)
Step-by-step solution
Nitrogen (Group 15) and Oxygen (Group 16) belong to the second period of the periodic table. As we move from left to right across a period, electrons are added to the same principal shell while protons are added to the nucleus. This results in an increase in the effective nuclear charge, which pulls the electron cloud closer to the nucleus. Consequently, the atomic radius decreases from left to right across a period. Therefore, the atomic radius of oxygen is indeed smaller than that of nitrogen. Thus, both Assertio