2023 H2 Chem P1 Q2 — Chemical bonding Solution

The answer is C (\(\text{YCl}\) and \(\text{ZO}_2\)).
The greater the difference in electronegativity between the two elements, the greater the ionic character.
• \(\text{XCl}_2\): \(3.0 - 1.2 = 1.8\)
• \(\text{Y}_2\text{O}\): \(3.5 - 0.9 = 2.6\)
• \(\text{XO}\): \(3.5 - 1.2 = 2.3\)
• \(\text{YCl}\): \(3.0 - 0.9 = 2.1\)
• \(\text{ZO}_2\): \(3.5 - 1.8 = 1.7\)
• \(\text{ZCl}_4\): \(3.0 - 1.8 = 1.2\)
C: \(\text{YCl}\) (2.1) has a larger difference than \(\text{ZO}_2\) (1.7), so the first compound is more ionic. Correct.
A: \(\text{XCl}_2\) (1.8) has a smaller difference than \(\text{Y}_2\text{O}\) (2.6), so the first compound is less ionic.
B: \(\text{XO}\) (2.3) has a smaller difference than \(\text{Y}_2\text{O}\) (2.6), so the first compound is less ionic.
D: \(\text{ZCl}_4\) (1.2) has a smaller difference than \(\text{XCl}_2\) (1.8), so the first compound is less ionic.