What is the charge of the ammonium ion (NH_4)?

• A. 0
• B. +1
• C. +2
• D. -1

Answer: (B)

Verified step by step guidance

1. Recall that the ammonium ion is represented as \(\mathrm{NH_4^+}\), which means it is a polyatomic ion composed of one nitrogen atom and four hydrogen atoms.
2. Understand that nitrogen typically has 5 valence electrons, and each hydrogen has 1 valence electron, so the total number of valence electrons before ion formation is \$5 + 4 \times 1 = 9$ electrons.
3. Recognize that the ammonium ion carries a positive charge, which means it has lost one electron compared to the neutral combination of nitrogen and hydrogen atoms.
4. Therefore, the overall charge of the ammonium ion is \(+1\), indicating it has one fewer electron than the total number of protons in the atoms combined.
5. Conclude that the charge of the ammonium ion \(\mathrm{NH_4}\) is \(+1\), which is why it is written as \(\mathrm{NH_4^+}\).