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Q. The Maximum Covalency Of Boron Is 4. Why?

My Main Doubt IS That the Ground State Electronic Configuration Of Boron is 1s22s2 2p1

So When It Exhibits Covalency of 4, what is its electronic configuration? Please include this electronic

configuration in your answer.

The electronic configuration of  Boron (At No 5)  is 1s2 2s2 2p1 . So, there are only two shells. The second shell contains one 2s orbitals and three 2p orbitals resulting total four orbitals in second shell. The total number of orbitals available in valence shell is known as covalency whether orbitals are completely filled or empty . Therefore, Boron  is restricted to a maximum covalency of 4 since only four (one s and three p) orbitals are available for bonding. 

The electronic configuration of  Boron is 1s2 2s2 2p1 while at excited state, the one of 2s electron can be promoted to one of empty orbital of 2p having equivalent energy resulting  1s2 2s1 2p2 electronic configuration.

Hence, Boron has 3 valence electrons with maximum 4 covalency. 

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hey @paramdeep:

the electronic configuration u r talking about is actually the electronic configuration at ground state,wat is to be added is that after that boron takes energy from surrounding and undergoes excitation state and the electrom pair from 2S orbital splits up and one electron from 2s orbital is promoted to 2Py orbital.

i.e now electronic configuration is :1S2 2S1 2Px1 2Py1 2Pz0

i.e in total 4 unpaired electrons are formed hence it's valency is 4

hope ite helps!

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Thanks For A Reply,

But In The Excited State You're Talking About ( 1s2  2s1 2px1 2py1  2z0 ) There are Clearly, only 3 unpaired electrons and certainely NOT 4.

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hey @paramdeep:

sorry mate,failed to realise atomic no. of boron is 5

and ya its nt 4 its 3 actually

sorry for mistake

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No Problem, Thanks Again.

To Meritnation--> Kindly Answer This Question, I've been waiting for 1 day.

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