List the following gas-phase ion pairs in order of the quantity of energy released when they form from separated gas-phase ions. List the pair that releases the least energy first. Na⁺ F^-, Mg²⁺F^-, Na⁺O^2-, Mg²⁺O^2-, Al³⁺O^2-.

Verified step by step guidance

1. Understand that the energy released when forming an ion pair is related to the lattice energy, which depends on the charges of the ions and the distance between them.
2. Recall that lattice energy increases with the charge of the ions and decreases with the size of the ions.
3. Identify the charges of the ions in each pair: Na^+ F^- (1+, 1-), Mg^{2+} F^- (2+, 1-), Na^+ O^{2-} (1+, 2-), Mg^{2+} O^{2-} (2+, 2-), Al^{3+} O^{2-} (3+, 2-).
4. Rank the ion pairs based on the product of their charges, which is a key factor in determining the energy released: Na^+ F^- (1), Mg^{2+} F^- (2), Na^+ O^{2-} (2), Mg^{2+} O^{2-} (4), Al^{3+} O^{2-} (6).
5. List the ion pairs in order of increasing energy released: Na^+ F^-, Mg^{2+} F^- or Na^+ O^{2-}, Mg^{2+} O^{2-}, Al^{3+} O^{2-}.

Key Concepts

Lattice Energy

Lattice energy is the amount of energy released when gaseous ions combine to form an ionic solid. It is influenced by the charges of the ions and the distance between them. Higher charges and smaller ionic radii typically result in greater lattice energy, indicating stronger ionic bonds and more energy released during formation.

Ion Charge and Size

The charge and size of ions significantly affect the energy released during ion pair formation. Ions with higher charges (e.g., Mg2+ vs. Na+) will attract each other more strongly, leading to greater energy release. Additionally, smaller ions can get closer together, further increasing the attractive forces and energy released.

Comparison of Ionic Compounds

When comparing different ionic compounds, the total energy released during formation can be assessed by considering both the charges and sizes of the ions involved. For example, comparing Na+F- and Mg2+F- involves evaluating the higher charge of Mg2+, which typically results in more energy released than Na+ despite Na+ being smaller.