The mixing together of the 2s and 2px atomic orbitals forms two new molecular orbitals: a bonding molecular orbital (σ bonding) and an antibonding molecular orbital (σ* antibonding). This process is known as hybridization.
When the 2s orbital and the 2px orbital combine, they undergo sp hybridization to form two sp hybrid orbitals. These sp hybrid orbitals are oriented linearly along the axis between the two atoms involved in the bonding. One of the sp hybrid orbitals is a bonding orbital (σ bonding) that is lower in energy and contributes to the stability of the molecule. The other sp hybrid orbital is an antibonding orbital (σ* antibonding) that is higher in energy.
This type of hybridization commonly occurs in molecules such as BeH2, where beryllium (Be) forms two sigma bonds with two hydrogen (H) atoms. The two sp hybrid orbitals of beryllium overlap with the 1s atomic orbitals of the hydrogen atoms, resulting in the formation of two sigma bonds.
Overall, hybridization allows for the formation of stronger and more stable bonds between atoms by maximizing the overlap of atomic orbitals and promoting effective sharing of electrons.