Electronic configuration has 2 electrons in k shell and 4 electrons in L shell.
In order to attain the noble gas configuration, carbon should either gain 4 electrons or lose 4 electrons or can share it's 4 electrons with some other element.
Gainof4electronsto form octet , 8 electrons in C⁴‐ anion is difficult because then a nucleus with 6 protons will uave to hold extra four electrons.
Lossof4electronsto attain duplet , 2 electrons like He atom in C⁴+ cation is difficult as it requires large amount of energy to remove four electrons.
Carbon , hence overcomes this difficulty by sharingitsfourvalance electrons with other atoms of carbonor with atoms of other elements. Theseelectronscontributedbytheatomsformutualsharinginordertoacquirethestablenobleconfigurationiscalledcovalencyofthatatom.Hence carbon shows tetracovalency.
The simplest molecule formed by sharing electrons, cvalent bonds can represent by electron dot structure.
