Question

Assertion :Size of atoms of inert gases are smaller than those of the preceding halogens. Reason: Covalent or van der Waals' radii generally decreases with increase in atomic number along a period.

Read both assertion and reason and choose the correct option regarding it.

• 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

Answer 1

The correct option is D Assertion is incorrect but Reason is correct

As we move along a period, atomic size increases because attraction forces increase. After nitrogen, atomic size increases for Oxygen and then decreases for fluorine.

The size of atoms of inert gases is larger than those of the preceding halogens. As we move towards in a period, the nuclear charge increases by 1 unit in each succeeding element while the number of shells remains the same.

The covalent and van der Waals radii with an increase in the atomic number as we move from left to right in a period. The alkali metals at the extreme left of the periodic table have the largest size in a period. The halogens at the extreme right of the periodic table have the smallest size.