Question

If the radius of an element X of electronic configuration is 2, 8, 3 is $0.76A^0$, the radius of element Y of electronic configuration 2, 8, 5 is:

• A. $0.64A^0$
• B. $0.76A^0$
• C. $0.88A^0$
• D. $1.08A^0$

Answer 1

The correct option is A $0.64A^0$

The element X and Y both have $3$ shells and hence belongs to the third period. Y has more electrons than X and hence is placed to the right of X. The atomic size decreases along the period. Hence the size of Y is smaller than X. The correct answer is option A.