IIT JEE , AIEEE Forum - Chemistry , Physical Chemistry - Molecular Orbital Theory:Finding Bond Order

vivek_aero

I'm not able to understand the procedure to find the bond order of a molecule in MOT.Please give me some tips.

arun-rashi

it is very detail theory but i give you some tip for objective.number of covalent bond between atoms is known as bond order of this molecule.for example H2 1,O2 2,N2 3,NO 2.5He2 zero etc.as the bond order increases bond dissosiation energy increases bond length decreases.inert gases bond order is 0 so they cannot exist as molecule.BOND ORDER =bonding electron -antibonding electron /2

arun-rashi

one thing always remember that electron filling in case of nitrogen and oxygen is different so study these diagram properly.

master_purav

Here is a short-cut trick

1) F2 18
2) O2 16
3) N2 14
2) C2 12
1) B2 10

Here left-most number is bond order, middle one are standard molecules and rightmost one is the number of electrons.

Calculate the total number of electrons in the given molecule and check out the bond order.

Eg (OH)-1
Number of electrons = 8+1+1 = 10
So from table bond-order is 1

Similarly if you get no. of electrons as example 13 the bond order is 2.5 (between 2 and 3 from table)

But you will have to memorize this table (which i dont think is much difficult)...

bishnunarayan

All this conventional methods are simply BAKWAAS............................U wont believe I find the bond order in jusr 4-5 seconds..............But this is just for the sake of those entrance exams where u do not have to show the procedure................For BOARD exams first write the electronic configuration and then,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, O.5 (Bonding - Anti bonding )

master_purav

Can you please explain how can you find bond orde in just 4-5 seconds???

If you have a shorter method then come on...

Selvaganesh_i

Hey master_purav

i think bond order of aluminium(13) is 2 and not 2.5.....

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