The degree to which a given bond is ionic or covalent is determined by calculating the difference in electronegativity between the two atoms involved in the bond. The two chlorine atoms share the pair...The degree to which a given bond is ionic or covalent is determined by calculating the difference in electronegativity between the two atoms involved in the bond. The two chlorine atoms share the pair of electrons in the single covalent bond equally, and the electron density surrounding the Cl2 molecule is symmetrical.