Question

a) Assign the position of the element having outer electronic configuration in the periodic table
(i) ${ns}^{2}n{p}^4$ for $n=3$ (ii) $(n-1)d^{2}n{s}^2$ for $n=4$
b) The size of ${Na}^{+}$ cation is smaller than $Na$. Explain.

Answer 1

$\left(a\right)\left(i\right)n{s}^{2}npq$ for n=3 $3s^{2}3p^4$

period - 3rd group - ${16}^{th}$ element is sulphur

(ii) $(n-2)a^{2}n{s}^2$ n=4

$(4-2)a^{2}4s^2$

$3a^{2}4s^2$

period- $4^{th}$ Group = $4^{th}$ element is titanium

(b) cation are smaller then percent atom due to reduced electron-electron repulsion.

Na 156 pm $1s^{2}2s^{2}2p^{6}3s^1$

$N{a}^{+}$ 95 pm $1s^{2}2s^{2}2p^6$