Test 3 Q7

[Rebecca Chu 1C]

It asks to circle which compound has the highest ionic character and the compounds were KBr or NaBr. Why does KBr have a more ionic character than NaBr? I circled NaBr because I thought Na has a higher electronegativity than K so NaBr has a higher ionic character, but I got it wrong.

[Chem_Mod]

More ionic character is determined by greater difference in electronegativity. Br is more electronegative than all metals, so a less electronegative metal will make a more ionic bond with Br.

[Andrew Evans - 1G]

I thought of it as Na is smaller, so has the same charge as K, but in a smaller volume (so it has greater charge density). Since it has a greater charge density, it has greater polarizing power, which pulls on Br's electron cloud more, causing greater distortion making the bond have more covalent character. This would mean KBr would have more ionic character.

-Andrew Evans
Section 1G

[Ismail 1F]

It has a greater electronegativity and higher electron density which makes it more ionic.