Question

question 10 of 10
how are prefixes used to name compounds?

a. prefixes are used to indicate the number of atoms in both covalent and ionic compounds.

b. prefixes are used to tell how many of each kind of atom are in ionic compounds.

c. prefixes are used to tell how many of each kind of atom are in covalent compounds.

d. a prefix is used only for the name of the second element in covalent compounds.

Explanation:

To determine the correct answer, we analyze each option:

• Option A: Prefixes are not used in ionic compounds (ionic compounds use ion charges and ratios, not prefixes for atom counts), so A is incorrect.
• Option B: Ionic compounds are named using ion charges and formula unit ratios, not prefixes to indicate atom counts, so B is incorrect.
• Option C: In covalent compounds (formed by non - metals sharing electrons), prefixes (like mono -, di -, tri - etc.) are used to show the number of each type of atom. For example, in $CO_2$ (carbon dioxide), the "di - " prefix shows there are 2 oxygen atoms. This is correct.
• Option D: In covalent compounds, the first element can also have a prefix (e.g., "mono - " in "monoxide" for $CO$, although "mono - " is often omitted for the first element if there is only one atom, but it can be used). So the statement that a prefix is used only for the second element is incorrect.

Answer:

C. Prefixes are used to tell how many of each kind of atom are in covalent compounds.