The bond length between two carbon atoms in a molecule of ethylene C2H4 is given as the distance between the nuclei of the two carbon atoms, which is 1.33 angstroms . To determine the percent ionic character of the carbon-carbon bond, we need to consider the electronegativity difference between the two carbon atoms. Since both atoms are carbon, their electronegativity values are the same 2.55 . The electronegativity difference is therefore 0. Percent ionic character can be estimated using the equation:Percent ionic character = 100 1 - exp -0.25 electronegativity difference ^2 In this case, since the electronegativity difference is 0, the equation becomes:Percent ionic character = 100 1 - exp -0.25 0 ^2 = 100 1 - exp 0 = 100 1 - 1 = 0%The percent ionic character of the carbon-carbon bond in ethylene is 0%, indicating that the bond is purely covalent.