My exam is tomorrow,  please answer Fast . Thanks in advance .. 
In NCERT TB pg 117 ,right side, 1st para , it has been given that in sp hybridisation of BeCl2 , "each of the sp hybridized orbital overlaps with the 2p orbital of chlorine axially and forms two Be-Cl sigma bonds . " 
but , the elect. Config of chlorine is 1s2 2s2 2p6 3s2 3p5 .  As per this , Be has to overlap axially with 3p orbital of chlorine .  It cannot overlap with 2p as it it already filled . But the textbook has mentions that it overlaps with 2p .... Plz explain this .... Thanks in advance .

Asked by Saravanan | 19th Jun, 2014, 04:57: PM

Expert Answer:

  • Ground state electronic configuration of Be: 1s22s2
  • In the excited state one of the 2s-electrons is promoted to vacant 2p orbital.
  • One 2s and one 2p orbital gets hybridised to fom two sp hybridised orbitals.
  • Each Be-Cl bond arises by axial overlap of a sp hybrid orbital on beryllium with a 3p orbital on chlorine.

Answered by Vaibhav Chavan | 20th Jun, 2014, 11:55: AM