Question

Each response below lists an ion by name and by chemical symbol or formula. Also each ion is classified as monatomic or polyatomic and as a cation or anion. Which response contains an error?

A. hydroxide / OH / monatomic / anion
B. carbonate / CO⁻ / polyatomic / anion
C. ammonium / NH⁴⁺ / polyatomic / cation
D. magnesium / Mg²⁺ / monatomic / cation
E. sulfite / SO₃²⁻ / polyatomic / anion

Answer 1

The response with an error is A. hydroxide / OH- / monatomic / anion; hydroxide is not monatomic, but a polyatomic ion because it consists of oxygen and hydrogen atoms.

Step-by-step explanation:

The response that contains an error is A. hydroxide / OH- / monatomic / anion. Hydroxide (OH-) is not a monatomic ion; rather, it is a polyatomic ion because it consists of more than one atom (oxygen and hydrogen). The rest of the responses correctly classify the ions:

• Carbonate / CO32- / polyatomic / anion
• Ammonium / NH4+ / polyatomic / cation
• Magnesium / Mg2+ / monatomic / cation
• Sulfite / SO32- / polyatomic / anion

The error occurred because hydroxide was incorrectly classified as monatomic, whereas it is actually polyatomic, containing one oxygen and one hydrogen atom.