Which of the following is the correct chemical formula for the ammonium ion?

• A. NH_3
• B. NH_2^+
• C. NH_4^+
• D. NO_3^-

Answer: (C)

Verified step by step guidance

1. Understand that an ion is a charged species formed when atoms or groups of atoms gain or lose electrons.
2. Recall that the ammonium ion is a polyatomic ion formed by the combination of ammonia (NH_3) with an additional hydrogen ion (H^+).
3. Recognize that ammonia (NH_3) is neutral, and when it gains a proton (H^+), it forms the ammonium ion with a positive charge.
4. Write the chemical formula for the ammonium ion by adding one hydrogen atom to NH_3 and indicating the positive charge: \(NH_4^+\).
5. Compare the given options and identify that \(NH_4^+\) correctly represents the ammonium ion, while \(NH_3\) is neutral ammonia, \(NH_2^+\) is not the ammonium ion, and \(NO_3^-\) is the nitrate ion.