Types of Bonds can be predicted by calculating the difference in electronegativity.
If, Electronegativity difference is,
Less than 0.4 then it is Non Polar Covalent
Between 0.4 and 1.7 then it is Polar Covalent
Greater than 1.7 then it is Ionic
For CaCl₂,
E.N of Chlorine = 3.16
E.N of Calcium = 1.00
________
E.N Difference 2.16 (Ionic Bond)
For C-H Bond in C₆H₁₂O₆,
E.N of Carbon = 2.55
E.N of Hydrogen = 2.20
________
E.N Difference 0.35 (Non-Polar Covalent Bond)
For C-O Bond in C₆H₁₂O₆,
E.N of Oxygen = 3.44
E.N of Hydrogen = 2.55
________
E.N Difference 0.89 (Polar Covalent Bond)
For O-H Bond in C₆H₁₂O₆,
E.N of Oxygen = 3.44
E.N of Hydrogen = 2.20
________
E.N Difference 1.24 (Polar Covalent Bond)
For MgO,
E.N of Oxygen = 3.44
E.N of Magnesium = 1.31
________
E.N Difference 2.13 (Ionic Bond)
For Na₂O,
E.N of Oxygen = 3.44
E.N of Sodium = 0.93
________
E.N Difference 2.51 (Ionic Bond)
For SiO₂,
E.N of Oxygen = 3.44
E.N of Silicon = 1.90
________
E.N Difference 1.54 (Polar Covalent Bond)
Result:
Compounds having Ionic Bonds are Na₂O, MgO and CaCl₂.