Which of the following correctly describes the Lewis dot structure of the ammonium ion, NH_4^+?

• A. Nitrogen is bonded to three hydrogen atoms with one lone pair, and the structure carries a negative charge.
• B. Nitrogen is bonded to four hydrogen atoms with no lone pairs, and the structure carries a positive charge.
• C. Nitrogen is bonded to four hydrogen atoms with one lone pair, and the structure is neutral.
• D. Nitrogen is bonded to three hydrogen atoms with no lone pairs, and the structure is neutral.

Answer: (B)

Verified step by step guidance

1. Step 1: Identify the total number of valence electrons available for the ammonium ion, NH_4^+. Nitrogen has 5 valence electrons, each hydrogen has 1 valence electron, and since the ion has a +1 charge, subtract one electron from the total count.
2. Step 2: Determine the bonding arrangement. Ammonium ion consists of one nitrogen atom bonded to four hydrogen atoms. Since it is an ion with a positive charge, the nitrogen will share electrons with all four hydrogens.
3. Step 3: Draw the Lewis structure by placing nitrogen in the center and connecting it to four hydrogen atoms with single bonds. Each bond represents a pair of shared electrons.
4. Step 4: Check for lone pairs on nitrogen. Since nitrogen uses all its valence electrons to form bonds with four hydrogens and the ion has a positive charge, there are no lone pairs on nitrogen in this structure.
5. Step 5: Confirm the overall charge of the structure. The ammonium ion carries a +1 charge, consistent with the loss of one electron from the total valence electrons, and the structure has nitrogen bonded to four hydrogens with no lone pairs.