Question

arrange the compounds below in decreasing order of the ionic character of the bonds in them. that is, pick 1 for the compound with the most ionic bonds, pick 2 for the compound with the next most ionic bonds, and so on.

Explanation:

Ionic character depends on electronegativity difference (ΔEN): larger ΔEN = more ionic. Electronegativities: K≈0.82, F≈3.98, S≈2.58, Se≈2.55.

• KF: ΔEN = 3.98 - 0.82 = 3.16 (largest, most ionic)
• SeF₂: ΔEN = 3.98 - 2.55 = 1.43
• SF₂: ΔEN = 3.98 - 2.58 = 1.40
• F₂: ΔEN = 0 (smallest, least ionic)

Order from most to least ionic: KF > SeF₂ > SF₂ > F₂.

Answer:

1 (most ionic): KF
2: SeF₂
3: SF₂
4 (least ionic): F₂