Electrons covalent bonding and

Instead of following conventional classifications, it would be reasonable to classify the intermolecular forces into three categories on the basis of their origin [2]. The first is the forces caused by the electronic polarization, i.e. van der Waals attraction, such as London dispersion (electronic polarization-electronic polarization) and Debye interaction (dipole-dipole-induced electronic polarization). The second is the forces caused by the electrostatic charges and/or the dipoles of the molecule these forces are based on the molecular structure and are independent of electronic polarizability. And the last category is the forces caused by exchange of elemental particles, such as an electron (covalent bond) and a proton (hydrogen bond). 

When atoms other than the noble gas atoms form bonds, they often have eight electrons around them in total. For example, the unpaired electron of a chlorine atom often pairs with an unpaired electron of another atom to form one covalent bond. This gives the chlorine atom an octet of eight electrons around it two from the two-electron covalent bond and six from its three lone pairs. This helps us explain why chlorine gas is composed of CI2 molecules. 

Ch. 9), to form the saltlike nitrides. Bonding with the transition metals occurs mostly by the sharing of electrons (covalent bonds) and by metallic bonding. Bonding with boron, aluminum, and silicon is essentially covalent (see Ch. 12). 

---