Question

The elements A and B have electronic configuration(2,8,18,2) and (2,6) respectively.

(a) To which period A and B belong ?

(b) To which group A and B belong ?​

Answer 1

Answer:

a) A belongs to the 4th period. As the element has 4 shells.

B belongs to the 2nd period. As it has 2 shells.

b) A belongs to the 2nd group. Valence electrons = 2

B belongs to the 16th group. Valence. electron =6 which is more than 3 so 6 + 10.

Hope it helpzzz....

Answer 2

a) Fourth and Second respectively

b)12th and 16th group respectively

Explanation:

The first period can accomodate 2 electrons  (1s²)

The second period can accomodate 8 electrons (2s²2p⁶)

The third period can accomodate 8 electrons (3s² 3p⁶)

The fourth period can accomodate 8 electrons (4s² 3d¹⁰ 4p⁶)

so , A goes to fourth period ,B goes to second period

B has 1s²2s²2p⁴

6 electrons in its ultimate shell and belongs to Group VIA (16th group)

A has 1s²2s²2p⁶3s² 3p⁶4s² 3d¹⁰

it belongs to 10+2 = 12th group