Multiple Choice
Which of the following statements correctly describes the Lewis dot structure for the ion formed from SnBr2?
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11. Bonding & Molecular Structure
Lewis Dot Structures: Ions
Multiple Choice
Which of the following statements correctly describes the Lewis dot structure of the AsO2^- ion?
A
Arsenic is the central atom, bonded to two oxygen atoms, both with double bonds; the negative charge is located on the arsenic atom.
B
Arsenic is the central atom, bonded to two oxygen atoms, both with single bonds; the negative charge is located on the arsenic atom.
C
Arsenic is the central atom, bonded to two oxygen atoms, both with single bonds; the negative charge is located on one of the oxygen atoms.
D
Arsenic is the central atom, bonded to two oxygen atoms, with one double bond and one single bond; the negative charge is located on the singly bonded oxygen.
Verified step by step guidance1
Identify the central atom in the AsO2^- ion. Since arsenic (As) is less electronegative than oxygen (O), arsenic will be the central atom bonded to two oxygen atoms.
Determine the total number of valence electrons available. Arsenic has 5 valence electrons, each oxygen has 6, and there is an extra electron due to the negative charge, so total electrons = 5 + (2 × 6) + 1 = 18 electrons.
Draw single bonds between arsenic and each oxygen atom, using 2 electrons per bond, and then distribute the remaining electrons to satisfy the octet rule for oxygen and arsenic as much as possible.
Consider resonance structures and formal charges to find the most stable Lewis structure. Assign one double bond between arsenic and one oxygen atom, and one single bond between arsenic and the other oxygen atom. Place the negative charge on the singly bonded oxygen to minimize formal charges.
Verify that the total number of electrons used matches the total valence electrons and that the octet rule is satisfied for all atoms where possible, confirming the correct Lewis structure has arsenic bonded to two oxygens with one double bond and one single bond, and the negative charge on the singly bonded oxygen.
