What is the nature of the ca-cl bond in a molecule of calcium chloride (cacl2) if the electronegativity value of calcium is 1.0 and that of chlorine is 3.16?

Ca-Cl is an ionic bond. We know this because the difference between their electronegativities is 2.16.
The electronegativity tells us which atom will attract the electron more than the other. Hence, chlorine attracts the electron a lot more than the calcium.
A difference of more than 1.6 (or 1.7 depending on the source) implies that the electrons are so unevenly shared, that the bond is ionic, rather than polar covalent.

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