Question

which pair of ions can form an ionic bond with each other and why?
o cu⁺ and ag⁺; they are both metal ions.
o s²⁻ and o²⁻. they have like charges.
o br⁻ and al⁻. they are both halogen ions.
o li⁺ and br⁻; they have unlike charges.

Explanation:

Step1: Recall ionic - bond formation

Ionic bonds form between ions with opposite charges. Cations (positively - charged ions) and anions (negatively - charged ions) attract each other to form an ionic bond.

Step2: Analyze each option

• Option 1: $\text{Cu}^+$ and $\text{Ag}^+$ are both cations. Like - charged ions repel each other and cannot form an ionic bond.
• Option 2: $\text{S}^{2 - }$ and $\text{O}^{2 - }$ are both anions. They have like charges and will repel, so they cannot form an ionic bond.
• Option 3: $\text{Br}^-$ is a halogen ion, but $\text{Al}$ forms $\text{Al}^{3+}$ (not $\text{Al}^-$). Also, two anions or two like - charged species do not form ionic bonds.
• Option 4: $\text{Li}^+$ is a cation and $\text{Br}^-$ is an anion. They have unlike charges and can attract each other to form an ionic bond.

Answer:

Li⁺ and Br⁻; They have unlike charges.