Multiple Choice
Which of the following statements correctly describes the Lewis dot structure of the Br\(_3^-\) ion?
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11. Bonding & Molecular Structure
Lewis Dot Structures: Ions
Multiple Choice
Which of the following correctly represents the Lewis dot structure for the ammonium ion, NH_4^+?
A
A nitrogen atom with three hydrogen atoms bonded and one lone pair, with a negative charge indicated.
B
A nitrogen atom surrounded by four hydrogen atoms, each connected by a single bond, with no lone pairs on nitrogen and a positive charge indicated.
C
A nitrogen atom with four hydrogen atoms bonded, one lone pair on nitrogen, and a positive charge indicated.
D
A nitrogen atom with four hydrogen atoms bonded, each hydrogen having a lone pair, and no charge indicated.
Verified step by step guidance1
Recall that the ammonium ion, NH_4^+, consists of one nitrogen atom bonded to four hydrogen atoms with an overall positive charge.
Determine the total number of valence electrons: nitrogen has 5 valence electrons, each hydrogen has 1, so for NH_4, total valence electrons are 5 + 4(1) = 9. Since the ion has a +1 charge, subtract one electron, giving 8 valence electrons to distribute.
Arrange the atoms with nitrogen as the central atom bonded to four hydrogens. Each N-H bond uses 2 electrons, so 4 bonds use 8 electrons, which accounts for all valence electrons.
Since all valence electrons are used in bonding, there are no lone pairs left on nitrogen. The positive charge indicates the loss of one electron compared to the neutral molecule, consistent with the ion's charge.
Verify that the nitrogen atom has a full octet (8 electrons around it) and each hydrogen has 2 electrons (a full shell for hydrogen). This confirms the correct Lewis structure is nitrogen bonded to four hydrogens with no lone pairs and a positive charge.
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