NO, or nitric oxide, is a diatomic molecule composed of one nitrogen atom (N) and one oxygen atom (O). In the formation of NO, a total of 5 bonding molecular orbitals (MOs) are used.

1. Formation of Nitrogen Atom MOs
- Nitrogen atom has 5 valence electrons in its outermost shell (2s^2 2p^3).
- These electrons occupy the atomic orbitals of the nitrogen atom, with the 2s orbital containing 2 electrons and the 2p orbitals containing 3 electrons.
- The 2s and 2p atomic orbitals undergo hybridization to form 3 sp^2 hybrid orbitals.
- These hybrid orbitals combine with the 2p orbital of the oxygen atom to form 3 sigma (σ) bonds.

2. Formation of Oxygen Atom MOs
- Oxygen atom has 6 valence electrons in its outermost shell (2s^2 2p^4).
- These electrons occupy the atomic orbitals of the oxygen atom, with the 2s orbital containing 2 electrons and the 2p orbitals containing 4 electrons.
- The 2s and 2p atomic orbitals undergo hybridization to form 2 sp^2 hybrid orbitals.
- These hybrid orbitals combine with the 2p orbital of the nitrogen atom to form 2 sigma (σ) bonds.

3. Formation of Bonding MOs
- The 3 nitrogen sp^2 hybrid orbitals and the 2 oxygen sp^2 hybrid orbitals overlap to form a total of 5 bonding molecular orbitals.
- These bonding MOs are formed by the constructive interference of the overlapping atomic orbitals.
- The bonding MOs are lower in energy than the original atomic orbitals and contribute to the stability of the NO molecule.

Summary:
In summary, the formation of NO involves the hybridization of the atomic orbitals of both nitrogen and oxygen atoms, resulting in the formation of 3 sigma (σ) bonds between the nitrogen and oxygen atoms. These sigma bonds are formed by the overlap of the sp^2 hybrid orbitals. Overall, a total of 5 bonding molecular orbitals are used in the formation of NO.