Question

two carbon atoms cannot be linked together by more than 3 covalent bonds.why?

Answer 1

A carbon atom has atomic number 6.
It's electronic configuration is 2,4
To become stable it shares it's 4 electrons.
Two carbon atoms when linked together share 1 electron.After it now 3 electrons are left. Then these 3 electrons link by covalent bond to other atoms.So only 3 covalent bonds can be formed

Answer 2

Explanation:

since,there is a single bond between the two carbon atoms and both share their one atom therefore for completing its shell it need to combine with three atoms of carbon or other element . therefore it cannot be linked to more than 3 covalent bonds since its shell will be completed to become stable .