MEDICAL PHYSIOLOGY

Detailed explanation-1: -Covalent bonds exist as nonpolar or polar-covalent bonds. In nonpolar covalent bonds, electrons are shared equally between identical atoms, as in the homonuclear bond in H2, the double C-C bond of ethylene (C2H4), the triple C-C bond of acetylene (C2H2), or the quadruple Re-Re bond in Re2Cl82−.

Detailed explanation-2: -A covalent bond consists of the mutual sharing of one or more pairs of electrons between two atoms. These electrons are simultaneously attracted by the two atomic nuclei. A covalent bond forms when the difference between the electronegativities of two atoms is too small for an electron transfer to occur to form ions.

Detailed explanation-3: -A covalent bond that has an equal sharing of electrons (part (a) of Figure 4.4. 1) is called a nonpolar covalent bond.