Question

Which of the following pairs will form the most stable ionic bond?

• A. Na and Cl
• B. Mg and F
• C. Li and F
• D. Na and F

Hint:

Ionic bond stability increases with the charge density of the ions. The higher the charge and the smaller the ions, the more stable the ionic bond.

Answer 1

The Correct Option is B

The stability of an ionic bond depends on the difference in electronegativity between the two elements involved. A greater difference leads to a stronger ionic bond. Additionally, smaller ions tend to form more stable bonds due to the higher lattice energy. 
- Na and Cl: Sodium (Na) has a lower ionization energy and chlorine (Cl) has a high electron affinity, but the ionic bond formed is relatively weaker than others because Na is a larger ion.
- Mg and F: Magnesium (Mg) has a higher ionization energy and fluorine (F) has a very high electron affinity. The small size of F and the high charge density of Mg result in a highly stable ionic bond.
- Li and F: Lithium (Li) and fluorine (F) also form a stable bond due to the small size of both ions, but magnesium and fluorine have a higher lattice energy due to magnesium's higher charge.
- Na and F: Sodium (Na) and fluorine (F) form an ionic bond, but it is less stable than the Mg-F bond because Na has a lower charge density than Mg. Thus, the most stable ionic bond is formed between Mg and F due to the higher lattice energy and stronger electrostatic attraction between the ions.