based on formal charges, which of the following is the best lewis electron-dot diagram for h₃no?
a
h
|
n—o—h
|
h
(with lone pairs on n and o)

b
h
|
h—n—o:
|
h
(with lone pairs on o)

c
h
|
:o—n—h
|
h
(with lone pairs on o and n)

d
h
|
h—o—n:
|
h
(with lone pairs on n)

Question

based on formal charges, which of the following is the best lewis electron-dot diagram for h₃no?
a
h
|
n—o—h
|
h
 (with lone pairs on n and o)

b
  h
  |
h—n—o:
  |
  h
 (with lone pairs on o)

c
  h
  |
:o—n—h
  |
  h
 (with lone pairs on o and n)

d
  h
  |
h—o—n:
  |
  h
 (with lone pairs on n)

Accepted Answer

To determine the best Lewis electron - dot diagram for $H_3NO$ based on formal charges, we use the formula for formal charge: $FC = V - N - \frac{B}{2}$, where $V$ is the number of valence electrons of the atom, $N$ is the number of non - bonding electrons, and $B$ is the number of bonding electrons.

### Step 1: Calculate the total number of valence electrons
- Valence electrons of $H$: $1$ (and there are $3$ $H$ atoms, so $3\times1 = 3$)
- Valence electrons of $N$: $5$
- Valence electrons of $O$: $6$
- Total valence electrons: $3 + 5+6=14$

### Step 2: Analyze Option A
- For $N$: $V = 5$, $N = 2$ (non - bonding electrons), $B = 6$ (bonding electrons, as it is bonded to $3$ $H$ and $1$ $O$). $FC=5 - 2-\frac{6}{2}=5 - 2 - 3 = 0$
- For $O$: $V = 6$, $N = 4$ (non - bonding electrons), $B = 2$ (bonding electrons). $FC=6 - 4-\frac{2}{2}=6 - 4 - 1 = 1$
- For $H$ atoms: $V = 1$, $N = 0$, $B = 2$ (but each $H$ is bonded with $1$ bond, so $B = 2$ for the bond, $FC = 1-0 - 1=0$)
- Total formal charge: $0 + 1+0 + 0+0=1$ (matches the overall charge of $+ 1$ as seen in the diagram)

### Step 3: Analyze Option B
- For $N$: $V = 5$, $N = 0$, $B = 8$ (bonded to $3$ $H$ and $1$ $O$ with a single bond? Wait, no, let's re - calculate. If $N$ is bonded to $3$ $H$ and $1$ $O$ (single bond), $B = 8$ (4 bonds, each bond has 2 electrons). $FC=5-0-\frac{8}{2}=5 - 4 = 1$
- For $O$: $V = 6$, $N = 6$ (non - bonding electrons), $B = 2$ (bonding electrons). $FC=6 - 6-\frac{2}{2}=6 - 6 - 1=-1$
- Total formal charge: $1+( - 1)+0 + 0+0 = 0$, but the overall charge of the species is $+1$, so this is incorrect.

### Step 4: Analyze Option C
- For $O$: $V = 6$, $N = 4$, $B = 4$ (bonded to $N$ with a double bond? Wait, let's use the formula. $FC=6 - 4-\frac{4}{2}=6 - 4 - 2 = 0$
- For $N$: $V = 5$, $N = 2$, $B = 6$ (bonded to $O$, $2$ $H$ and $1$ $H$? Wait, $FC=5 - 2-\frac{6}{2}=5 - 2 - 3 = 0$
- But the overall charge here is shown as $+1$, but let's check the valence electrons. The structure in option C: Let's count the electrons. $O$ has 4 non - bonding, 4 bonding; $N$ has 2 non - bonding, 6 bonding; $H$ atoms. The total number of electrons: For $O$: $4 + 4=8$, for $N$: $2+6 = 8$, for $H$: $1\times3 = 3$. Total electrons: $8 + 8+3=19$, which is more than the total valence electrons of $14$ (we made a mistake in counting, actually, the correct way is to count the valence electrons in the Lewis structure. The total valence electrons should be $14$. In option C, the number of electrons is incorrect. Also, the formal charge sum: If we recalculate, for $O$: $V = 6$, $N = 4$, $B = 4$ (double bond), $FC=6 - 4-\frac{4}{2}=0$; for $N$: $V = 5$, $N = 2$, $B = 6$ (bonds to $O$, $2$ $H$ and $1$ $H$), $FC=5 - 2-\frac{6}{2}=0$; for $H$: $FC = 0$. But the overall charge of the species is $+1$, so the sum of formal charges should be $+1$, but here it is $0$, so incorrect.

### Step 5: Analyze Option D
- For $O$: $V = 6$, $N = 4$, $B = 4$ (bonded to $2$ $H$ and $N$), $FC=6 - 4-\frac{4}{2}=6 - 4 - 2 = 0$
- For $N$: $V = 5$, $N = 4$, $B = 2$ (bonded to $O$), $FC=5 - 4-\frac{2}{2}=5 - 4 - 1 = 0$
- For $H$ atoms: $FC = 0$
- Total formal charge: $0+0 + 0+0+0 = 0$, but the overall charge of the species is $+1$, so incorrect.

Among the options, Option A has a total formal charge of $+1$ (which matches the overall charge of the species) and the formal charges of the individual atoms are reasonable.

# Answer: A. $\ce{\overset{H}{\underset{H}{:N}-\overset{..}{O}-H}}$ (with the overall charge of $+1$ as shown in the diagram)

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QUESTION IMAGE

Question

Explanation:

Step 1: Calculate the total number of valence electrons

Step 2: Analyze Option A

Step 3: Analyze Option B

Step 4: Analyze Option C

Step 5: Analyze Option D

Answer: