Question

In a kilometre race a can beat b by 100m and b can beat c by 60m. In the same race a can beat c by

Answer 1

1) Beryllium Chloride (BeCl2)

* 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 BeCl2 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.