Question

ccc matter and energy explain how you would expect the strength of the ionic bonds in potassium bromide (kbr) to compare with that of the bonds in lithium bromide (libr).

Explanation:

Ionic bond strength depends on the distance between ions (related to ion size) and ion charges. In \(KBr\) and \(LiBr\), the anion (\(Br^-\)) is the same. The cation charge is \(+1\) for both \(K^+\) and \(Li^+\). But \(Li^+\) (\(r = 76\space pm\)) is smaller than \(K^+\) (\(r=138\space pm\)). Using Coulomb's law (\(F = k\frac{q_1q_2}{r^{2}}\), where \(q_1\) and \(q_2\) are ion charges and \(r\) is the distance between ions), a smaller \(r\) (for \(Li^+\) in \(LiBr\)) leads to a stronger force of attraction.

Answer:

The ionic bonds in \(LiBr\) are stronger than those in \(KBr\). This is because \(Li^+\) is smaller than \(K^+\). According to Coulomb's law (\(F = k\frac{q_1q_2}{r^{2}}\)), with the same - charged anion (\(Br^-\), \(q=- 1\)) and same - charged cation (\(q = + 1\) for both \(Li^+\) and \(K^+\)), a smaller inter - ionic distance (\(r\)) (due to smaller \(Li^+\)) results in a stronger electrostatic force of attraction (ionic bond strength) in \(LiBr\) compared to \(KBr\).