Question

The electronic confirgation of an elementsh B is 2,8,7 and it forms an ionic compound AB2 with another elements A what is the valency of elements A

Answer 1

Electronic configuration of B :
             2, 8 , 7
So valency of B :  -1 , as the last orbital will reach 8 (ideal gas config) by getting one more electron.

As B forms a compound  A B2,   A must have a valence = +2. The sum of valences of the atoms in a neutral compound is 0, Because  the compound  A B2 is neutral.

Answer 2

Heya.....

Configuration of B is,,, 2, 8, 7
Valency of B is,,, -1 coz last orbit has 8 ions...

** And B forms a compound AB2 , A have +2 the sum of valence electrons is 0 coz it is neutral,, .....

Be brainly.....