Question

The number of valence electrons in $O^{2-}$(Z = 8) ion is

• A. 6
• B. 4
• C. 8
• D. 2

Answer 1

The correct option is C

8

The correct option is (C).

Explanation of correct option is:

1. Valence electrons are those which are present on the outermost orbit or valence shell of an atom.
2. The atomic number of oxygen is 8.
3. Oxygen contains 6 valence electrons, as the electronic configuration of oxygen is 2,8.
4. In $O^{2-}$ion, 2 more electron is present. So, the valence electrons in the $O^{2-}$ion are 8.

Explanation of incorrect option:

Option (A): Neutral oxygen atom has a 6 valence electron.

Option (B): Silicon has a 4 valence electron.

Option (D): Magnesium has 2 valence electron.

Thus, The number of valence electrons is $O^{2-}$(Z = 6) ion is 8.