Question

question 5 of 10
why are prefixes not used in naming ionic compounds?

a. a roman numeral is used instead of a prefix.

b. a subscript follows each name instead of a prefix.

c. two ions can combine in only one combination.

d. the number of ions is not fixed in a compound.

Explanation:

To determine why prefixes are not used in naming ionic compounds, we analyze each option:

• Option A: Roman numerals are used for transition metals to indicate charge, not as a replacement for prefixes in general ionic compound naming. Eliminate A.
• Option B: Subscripts in formulas show ion ratios, but naming doesn't use subscripts or prefixes in the same way. Eliminate B.
• Option C: Ionic compounds form based on charge balance. For example, Na⁺ and Cl⁻ form NaCl (only one ratio). Since the ion combination ratio is fixed by charge, prefixes (used for covalent compounds with variable ratios) aren't needed. This makes C correct.
• Option D: The number of ions in an ionic compound is fixed by charge balance (e.g., Mg²⁺ and O²⁻ form MgO, a fixed ratio). So D is incorrect.

Answer:

C. Two ions can combine in only one combination.