Question

An element $X$ belongs to the third group and the fifth period of the periodic table. Which one of the following is true regarding the outer electronic configuration of $X?$

• A. $4d^{1}5s^2$
• B. $4d^{2}5s^2$
• C. $4d^{3}5s^2$
• D. $4d^{5}5s^1$

Answer 1

The correct option is A $4d^{1}5s^2$

Solution:

Given- Group number=$3$ so its outer valence shell must contain $3$ electron

Since, element 'X' belongs to fourth period, $n=5$.

So correct electronic configuration will be $4d^1,5s^2$

so option A is correct answer.