Question

the atomic number of beryllium is 4 while that of oxygen is 8.write down the electronic configuration of the both and deduce their valency from thevsame

Answer 1

Beryillium ......2,2. and valency +2
Oxygen.......2,6...and valency _2.....

Answer 2

first write symbols Be. O. Be have 2electron in first shell 2 in 2nd shell O have 2 electrons in first shell 6 in. second shell so (2-2)=0