Covalent bond homework

It is represented by two dashes (=). Double covalent bonds are much stronger than a single bond, but they are less stable. Example: Carbon dioxide molecule has one carbon atom with six valence electrons and two oxygen atom with four valence electrons.

Whether a bond is nonpolar or polar covalent is determined by a property of the bonding atoms called electronegativity. Electronegativity is a measure of the tendency of an atom to attract electrons (or electron density) towards itself. It determines how the shared electrons are distributed between the two atoms in a bond.

Electron dot structures of covalent molecules are written with respect to the octet rule . According to this rule, all the atoms in the molecule will have eight electrons in their valence shell except the Hydrogen atom. Hydrogen will have only two electrons because only two electrons complete its first shell to attain helium configuration.

The absolute values of the electronegativity differences between the atoms in the bonds H–H, H–Cl, and Na–Cl are 0 (nonpolar), 0.9 (polar covalent), and 2.1 (ionic), respectively. The degree to which electrons are shared between atoms varies from completely equal (pure covalent bonding) to not at all (ionic bonding).