IIT JEE , AIEEE Forum - Chemistry , Physical Chemistry

prathima

carbon atom can loose 4 electrons
to get octet it should get 4 ele.....
then y dont the c atom form 4 bonds with other c atom
they can share 4 ele..........
s?

prathima

cl has to get 1 ele....
two ci atoms form 1bond & both get octet

o has to get 2 ele.........
two o atoms form 2 bonds& both get octet

in the same way y dont c atoms form 4 bonds

prathima

plz some one explain

astronautameya

look, prathima,

this can be xplained based on the orientation of the orbitals about the carbon atom.

a pie bond is formed when two orbitals overlap above and below the plane of the sigma bond.
so, only 2 pie bonds can be formed.

whr do you xpect to accomodate the third pie bond???

prathima

thanks
thats fine

prathima

but i know nothing about formation of pie bonds
can any one explain

asmit

See,it is difficult to explain your query regarding pie bonds without figures.I would recommend you to consult Morrison Boyd organic chemistry and go to the chapter of benzene where excellent pictures are given showing the pie clouds above and below the ring.From those pictures,you will get a feel of what Astrounatemeya is trying to express.Consult your teacher in this regard.By the way,I think Astrounatameyas answer is correct.

jinav

see, electronic configuration of carbon is 1s2 2s2 2p2 which implies outermost orbital has only 2 elctrons to share........hope u got it ....some1 correct if i m wrong

srujana

prathima, observe the diagram

one of the p orbitals overlap by end on overlap and form sigma bond
the remaining p orbitals form pie bond by side on overlap. Thus there is no orbital left to form another pie bond.

The p orbital indicated by blue colour cant overlap with the orbital shown with yellow colour. Hence C4 bond is not possible.

Whereas the blue coloured orbital can overlap with the orbital of an other atom, shown with red colour

swashata4iit

See jinav the configuration of C-atom is 1s2 2s2 2p2. Here the outer most orbit is the orbit having principal quantum no 2. The total electron for this orbit is 4. Thus to complete its octate it needs 4 more electrons.

And for u prathime sinjan has given the right diagram. Besides this u should know the property of catenation of Carbon.

The UNIQUE property of carbon atom to combine with another C-atom to form a huge no. of compounds is called catenation

The basic condition for an element to exhibit catenetion is

1. It should have valency more than two or at least two
2. Bonds by the element with its own atoms should be stronger than the bond made by the element with other atom ESPECIALLY OXYGEN.

Go through the given data and ur concept will be clear.

Bond                                 Bond strength

   C---C                              355 kj/mole
   Si---Si                           200 kj/mole
   Si---O                           452 kj/mole
    C---O                           351 kj/mole
That is why although bearing same electronic configuration C-atom shows catenation whereas Si-atom does not.

Hope now everything is clear for You.

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