Why does carbon only share their electrons?

Electron 'sharing' occurs when the electrons in the outermost electron shell, or valence shell electrons, from one atom can be used to complete the outermost electron shell of another atom without being permanently transferred, as occurs in the formation of an ion. read more

Therefore a Carbon atom can instead share each of its electrons with four separate Hydrogen atoms. This completes the valence shells for four Hydrogen atoms and one Carbon atom. In this example, one pair of electrons is shared between two atoms. read more

Carbon atoms do share four pair of electrons as four single bonds or as one single bond and one triple bond or as two double bonds or as one double bond and two single bonds. sp3 hybridisation. But if you are asking as to why a carbon doesn't share all of its electrons with another carbon atom to form a molecule, then the answer is it can't. read more

Each Carbon needs 4 more electrons and each Hydrogen needs 1 more electron. Hydrogen shares its only electron with Carbon to get a full valence shell. Now Carbon has 5 electrons. Because each Carbon atom has 5 electrons--1 single bond and 3 unpaired electrons--the two Carbons can share their unpaired electrons, forming a triple bond. read more