The electronic configuration of 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 in second group?

iii) Which element belongs to 18th group?

i) The element ‘Z’ belongs to second period

Explanation:

As number of valence electrons decide the period of the element.

⇒ Element ‘X’ has not any valence electrons.

⇒ Element ‘Y’ has 6 valence electrons.

⇒ Element ‘Z’ has 2 valence electrons.

Thus, element ‘Z’ belongs to second period.

ii) The element ‘Y’ belongs to second group.

Explanation:

As total number of shells present in the element decide the group number.

⇒ Element ‘X’ has total one shell (2).

⇒ Element ‘Y’ has total two shells (2,6).

⇒ Element ‘Z’ has total three shells (2.8,2).

The element ‘Y’ belongs to second group.

iii) The element ‘X’ belongs to 18h group.

Explanation:

Element ‘X’ belongs to 18^th group because it has complete noble gas configuration (X=2). This means it is a noble gas which are placed in 18^th group.