Question

Assign the position of the element having outer electronic configuration,
(i) ns${}^2$np${}^4$ for n=3,

(ii) (n-1)d${}^2$ns${}^2$ for n=4, and

(iii) (n-2) f${}^7$(n-1)d${}^1$ ns${}^2$ for n=6 in the periodic table.

Answer 1

(i) For $n=3$, the period in which the element belongs is third. The electronic configuration is $3s^{2}3p^4$ and the element belongs to p block. The group number of the element is $10+$ number of electrons in the valence shell.
$=10+6=16$
Thus, the element belongs to third period and sixteenth group.

(ii) For $n=4$, the period in which the element belongs is fourth. The electronic configuration is $3d^{2}4s^2$ and the element belongs to d block. The group number of the element is $=$ number of electrons in the $(n-1)d$ subshell $+$ number of electrons in ns subshell$=2+2=4$
Thus, the element belongs to fourth period and fourth group.

(iii) For $n=6$, the period in which the element belongs is sixth. The electronic configuration is $4f^{7}5d^{1}6s^2$ and the element belongs to f block. All f block elements belong to third group.
Thus, the element belongs to sixth period and third group.