Amongst the following, the total number of species not having eight electrons around central atom in its outer most shell, is
 : 

Covalent bonds are formed by the sharing of electrons between two atoms so that both can achieve a completely filled _____________ shell.

Covalent molecules have low melting and boiling point because:

Which of the following options represents the correct Lewis structure for methane (CH₄)?

​Match List-I with List-II​

Select the correct option :