Question

The electronic configuration of the elements X, Y and Z are given below:
a) X = 2 b) Y = 2, 6 c) Z = 2, 8, 2
i) Which element belongs to second period?
ii) Which element belongs to second group?
iii) Which element belongs to 18th group?

Answer 1

a) X=2 b)Y=2,6 c)Z=2,8,2

1s${}^2$ 1s${}^2$ 2s${}^2$ 2p${}^4$ 1s${}^2$ 2s${}^2$ 2p${}^6$ 3s${}^2$.

i) 'Y' belongs to the 2nd period. Because its electronic configuration ends with n=2

ii) 'Z' belongs to the 2nd group as its last electron enters into the second group of s-subshell.

iii)'X' belongs to 18th group.