In the best Lewis structure for NO+, what is the formal charge on the N atom?
A) -1
B) 0
C) +1
D) +2
The correct answer and explanation is :
Correct Answer: C) +1
Explanation:
To determine the formal charge on the nitrogen atom in the best Lewis structure for NO⁺ (nitrosonium ion), follow these steps:
Step 1: Count Valence Electrons
- Nitrogen (N) has 5 valence electrons.
- Oxygen (O) has 6 valence electrons.
- Since the molecule has a +1 charge, we subtract 1 electron from the total count.
[
5 (N) + 6 (O) – 1 = 10 \text{ total valence electrons}
]
Step 2: Draw the Skeleton Structure
- N is less electronegative than O, so it is the central atom.
- Connect N to O with a single bond first and distribute electrons to satisfy the octet rule.
Step 3: Complete the Octets & Assign Formal Charges
- The best Lewis structure has a triple bond between N and O because it allows for the most stable configuration.
- This structure ensures both atoms have an octet and minimizes formal charges.
Formal charge is calculated using:
[
\text{Formal Charge} = \text{Valence Electrons} – \text{Nonbonding Electrons} – \frac{\text{Bonding Electrons}}{2}
]
For Nitrogen (N):
[
\text{Formal Charge} = 5 – 0 – \frac{6}{2} = 5 – 3 = +1
]
For Oxygen (O):
[
\text{Formal Charge} = 6 – 4 – \frac{6}{2} = 6 – 3 = 0
]
Step 4: Confirming Stability
- The best structure has a triple bond between N and O, and a +1 formal charge on nitrogen.
- This structure obeys the octet rule and minimizes formal charges.
Thus, the correct answer is C) +1.
Image Representation of the Lewis Structure:
tLewis structure for NO⁺
The image above shows the best Lewis structure for NO⁺ (nitrosonium ion), with a triple bond between N and O and a +1 formal charge on nitrogen, confirming that the correct answer is C) +1.