Question

arrange these ionic compounds in order of increasing magnitude of lattice energy: cao, kbr, kcl, sro
arrange these ionic compounds in order of increasing melting points: kcl, sro, rbbr, cao

Explanation:

Step1: Recall lattice - energy factors

Lattice energy is directly proportional to the product of ionic charges and inversely proportional to the ionic - radius sum. Melting point is related to lattice energy (higher lattice energy, higher melting point).

Step2: Analyze ionic charges and radii

For \(KBr\) and \(KCl\), \(K^+\) has a charge of \(+ 1\), \(Br^-\) and \(Cl^-\) have a charge of \(-1\). Since \(Br^-\) has a larger ionic radius than \(Cl^-\), the lattice energy of \(KCl>KBr\). For \(CaO\) and \(SrO\), \(Ca^{2 +}\) and \(Sr^{2+}\) have a charge of \(+2\), \(O^{2 -}\) has a charge of \(- 2\). Since \(Sr^{2+}\) has a larger ionic radius than \(Ca^{2+}\), the lattice energy of \(CaO>SrO\). Also, the ionic charges in \(CaO\) and \(SrO\) (\(+2\) and \(-2\)) are higher than in \(KCl\) and \(KBr\) (\(+1\) and \(-1\)), so \(CaO\) and \(SrO\) have higher lattice energies.

Step3: Arrange by lattice energy

For lattice energy: \(KBr

Step4: Relate lattice energy and melting point

Since melting point is related to lattice energy, for melting point: \(KBr

Answer:

For lattice energy: \(KBrFor melting point: \(KBr