The hybrid orbital set used by the central atom in no3- is and why? a. sp
b. sp3
c. SP2
d. sp3d2
e. sp3d

c. SP2

Explanation:

The image in the diagram below shows the structure of  NO₃⁻

Nitrogen is the central atom with the electronic configuration of 1s² 2s² 2p³.

So in its outermost shell, it has 3 electrons and the hybridization is sp²

However,

According to Hund's rule:

The ground state of Nitrogen is;    

1s²    2s²   2p³

↑↓     ↑      ↑  ↑  ↑

At the excited state when it is attached to 3 different oxygen ions, we have:

                1s²     2s²        2p⁵

O⁻ --->     ↑↓      ↑↓     ↑↓    ↑↓   ↑      

                1s²     2s²        2p⁵

O⁻ --->     ↑↓      ↑↓     ↑↓    ↑↓   ↑

                1s²     2s²        2p⁴

O⁻ --->     ↑↓      ↑↓     ↑↓    ↑   ↑

Thus, the 3 sp² orbital lies in a plane and form 3 N - O σ- bond and one π- bond.

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