Question

Element with electronic configuration as `[Ar]^(18)3d^(5)4s^(2)` is placed in `:`
A. `1^(st)`group, `s-` block
B. `2^(nd) ` group, `s-` block
C. `5^(th) ` group, `d-` block
D. `7^(th) ` group, `d-` block

Answer 1

Correct Answer - 4
Last electrons enters in `d-` orbital. So it belong to `d-` block. For `d-` block elements the group number is equal to the number of valence electrons `+` number of electrons in `(n-1)d` subshell `i.e., 2+5=7^(th)` group.