predict the predominant group of the element having atomic number 35, 17, 37 explain by writing electronic configuration.
Answers
Prediction of Period ⟶ In the electronic configuration of an atom, the principal quantum number (n) of the valence electrons represents the period of an element.
Prediction of Block ⟶ The orbital out of s,p,d and f which receives the last electron represents the block of an element
Prediction of Group ⟶ The group prediction occurs with the help of block as:-
(1) For s block: Group Number = Number of valence e−
(2) For d block: Group Number = Number of e− in (n−1)d subshell + number of e−in ns subshell
(3) For p block: Group Number = Number of valence e−+10
(4) For f-block: Group Number = 3(always)
For example for chlorine with Z=17
Electronic configuration = 1s22s22p63s23p5
Since the last e− enters in p - subshell:
(i) ∴ Block will be ′p′
(ii) For group we have element in p-block
∴ Group number = 10+ Valence e− in ssubshell + Valence e− in p subshell
Group Number = 10+2+5=17
(iii) For period
The quantum number of valence e−=3
∴ Period number = 3