3.30 Assign the position of the element having outer electronic configuration
(i)
ns2np4 for n=3 (ii) (n-1)d2ns2 for n=4, and (iii) (n-2) f 7 (n-1)d1ns2 for n=6, in the periodic table.

 (i) Since n = 3rd the element belongs to the 3rd period. It is a p–block element since the

last electron occupies the p–orbital.

There are four electrons in the p–orbital. Thus, the corresponding group of the element

= Number of s–block groups + number of d–block groups + number of p–electrons

= 2 + 10 + 4

= 16 

Therefore, the element belongs to the 3rd period and 16th group of the periodic table.

Hence, the element is Sulphur.

(ii)Since n = 4, the element belongs to the 4th period. It is a d–block element as d– orbitals

are incompletely filled.

There are 2 electrons in the d–orbital.

Thus, the corresponding group of the element

= Number of s–block groups + number of d–block groups

= 2 + 2 =

4

Therefore, it is a  4th period and 4th group element. Hence, the element is Titanium.

(iii) Since n = 6, the element is present in the 6th period. It is an f –block element

as the last electron occupies the f–orbital. It belongs to group 3 of the periodic table since

all f-block elements belong to group 3. Its electronic configuration is [Xe] 4 f7 5d16s2

Thus, its atomic number is 54 + 7 + 2 + 1 = 64. Hence, the element is Gadolinium.