Question

The atomic numbers of three elements A, B and C are given below :

(i) Which element belongs to group 18 ? (ii) Which element belongs to group 15 ?
(iii) Which element belongs to group 13 ? (iv) To which period/periods do these elements belong ?

Lakhmir Singh Chemistry Class 10

Answer 1

Answer:

inert gases belong to 18 groups

Answer 2

The atomic numbers of three elements A, B and C are given below :

Element                       Atomic number

     A                                         5

     B                                         7

     C                                        10

(i) Which element belongs to group 18 ?

Element C, as it is Neon an inert gas element which belongs to 18 group

(ii) Which element belongs to group 15 ?

Element B , which is nitrogen belongs to group 15

iii)Which element belongs to group 13 ?

element A, Boron belongs to group number 13

iv) To which period/periods do these elements belong ?

All these elements belong to second period