Question

list the following bonds in order of decreasing ionic character: the lithium - fluorine bond in lif, the phosphorus - chlorine bond in pcl₃, the sodium - iodine bond in nai, the hydrogen - sulfur bond in h₂s.

Explanation:

Step1: Recall electronegativity concept

The ionic character of a bond is determined by the electronegativity difference ($\Delta \chi$) between the two atoms in the bond. The greater the $\Delta \chi$, the higher the ionic character.

Step2: Find electronegativity values

Electronegativity values from the Pauling scale: Li = 0.98, F = 3.98, Na = 0.93, I = 2.66, H = 2.20, S = 2.58, P = 2.19, Cl = 3.16.

Step3: Calculate electronegativity differences

For Li - F: $\Delta \chi_{Li - F}=3.98 - 0.98=3.00$.
For Na - I: $\Delta \chi_{Na - I}=2.66 - 0.93 = 1.73$.
For P - Cl: $\Delta \chi_{P - Cl}=3.16 - 2.19 = 0.97$.
For H - S: $\Delta \chi_{H - S}=2.58 - 2.20 = 0.38$.

Step4: Order bonds by ionic character

Based on the $\Delta \chi$ values, the order of decreasing ionic character is Li - F > Na - I > P - Cl > H - S.

Answer:

Li - F > Na - I > P - Cl > H - S