Question

the atomic number of beryllium is 4 while that of axygen is 8. write down the electronic configration of the two and deduce their valency from the same.

Answer 1

the atomic number of beryllium is 4 while that of oxygen is 8.write down the electronic configuration of the both and deduce their ... Beryillium ......2,2. and ...

Answer 2

Hi friend,

Here is your answer,
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Valency of an atom is the number of electrons it need to lose or gain in order to reach noble gas atomic configuration.
(This definition was for to explain)

Beryllium :
Atomic number = 4
Shells                       :     K      L
Number of electrons :     2      2

Electronic configuration- 2 , 2
It needs to lose two electrons to reach noble gas configuration so the valency of Beryllium is 2-.

Oxygen :
Atomic number = 8
Shells                       :     K      L
Number of electrons :     2      6

Electronic configuration- 2 , 6
It needs to gain two electrons to reach noble gas configuration so the valency of Oxygen is 2+.
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