How many unpaired electrons does a oxygen atom (O) have in its ground state?

   In the ground-state electron configuration of oxygen, O, two  unpaired electrons are present.

Explanation:

To find out the number of unpaired electrons in oxygen, you need to write the electron configuration of O(Oxygen atom).

Remember that the atomic number of oxygen is 8.

Here is the ground state electron configuration of O:

1s²2s²2p⁴

=[He]2s²2p⁴

Remember that the p subshell has three orbitals.Each orbit can take maximum two electrons.

In case of filling degenerate orbits ,each orbital will take one electron before pairing by the second electron according to Hunds' rule.

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