Arrange these compounds in order of increasing magnitude of lattice energy: CaO, NaBr, CsI, BaS.

Verified step by step guidance

1. Understand that lattice energy is the energy required to separate one mole of an ionic solid into its gaseous ions. It is influenced by the charge of the ions and the distance between them.
2. Recall that lattice energy increases with increasing charge of the ions and decreases with increasing ionic radius (distance between ions).
3. Identify the charges of the ions in each compound: CaO (Ca²⁺ and O²⁻), NaBr (Na⁺ and Br⁻), CsI (Cs⁺ and I⁻), BaS (Ba²⁺ and S²⁻).
4. Compare the ionic radii: Cs⁺ and I⁻ are larger than Na⁺ and Br⁻, and Ba²⁺ and S²⁻ are larger than Ca²⁺ and O²⁻.
5. Arrange the compounds by considering both the charges and the ionic radii: CsI < NaBr < BaS < CaO.

Key Concepts

Lattice Energy

Lattice energy is the amount of energy released when gaseous ions combine to form an ionic solid. It is a measure of the strength of the forces between the ions in an ionic compound. Higher lattice energy indicates stronger ionic bonds, which typically results from smaller ions with higher charges.

Ionic Size and Charge

The size and charge of the ions in a compound significantly influence lattice energy. Smaller ions can pack more closely together, leading to stronger electrostatic attractions. Additionally, ions with higher charges produce stronger interactions, resulting in greater lattice energy compared to those with lower charges.

Trends in Lattice Energy

Lattice energy trends can be predicted based on the ionic compounds' composition. Generally, for compounds with similar ionic charges, lattice energy increases with decreasing ionic size. For example, comparing compounds like NaBr and CsI, NaBr has a higher lattice energy due to the smaller size of Na+ compared to Cs+.