Hybridization and unpaired unpaired electrons in the complex nickel chloride
Answers
The electronic configuration of 'Be' in ground state is 1s² 2s². Since there are no unpaired electrons, it undergoes excitation by promoting one of its 2s electron into empty 2p orbital.
Thus in the excited state, the electronic configuration of Be is 1s² 2s¹ 2p¹.
If the beryllium atom forms bonds using these pure orbitals, the molecule might be angular. However the observed shape of BeCI₂ is linear. To account for this, sp hybridization was proposed as explained below.
In the excited state, the beryllium atom undergoes 'sp' hybridization by mixing a 2s and one 2p orbitals. Thus two half filled 'sp' hybrid orbitals are formed, which are arranged linearly.
These half filled sp-orbitals form two σ bonds with two 'Cl' atoms.
Thus BeCl2 is linear in shape with the bond angle of 180o.