HW 3.77

[Jane Burgan 1C]

For each pair, determine which compound has bonds with greater ionic character: (a) HCl or HI; (b) CH4 or CF4;
(c) CO2 or CS2.

How do you tell which compound has greater ionic character?

[Bingcui Guo]

You can decide by calculating the difference in each element's electronegativity. So the answer should be HCl, CF4, and CO2.

[megansardina2G]

You look at the differences in electronegativity. In the sixth edition textbook, figure 3.12 shows most of the values you'll need (and all for this problem). Even if you aren't looking at the exact values, you can estimate it using electronegativity trends. Electronegativity increases across a period and decreases down a group. You can use this knowledge to see which bonds are more ionic: for example: Iodine and Chlorine are both in the same group (halogens), but I is farther down the group than Cl, so it is less electronegative than Cl and thus closer in electronegativity to H. Therefore, the bond between Cl and H is more ionic.

[John_Richey_4A]

Just look up which has a higher and lower electronegativity, and if they have a large difference, it's ionic.

[Miriam Sheetz 2B]

The greater the electronegativity difference, the greater the ionic character.