The lewis structure of HNO3 (nitric acid), what is the formal charge on nitrogen? (hint: the hydrogen is on a oxygen) +1 +2
The correct answer and explanation is :
Lewis Structure of HNO3:
- Count the Valence Electrons:
- Hydrogen (H) has 1 valence electron.
- Nitrogen (N) has 5 valence electrons.
- Oxygen (O) has 6 valence electrons, and there are 3 oxygens.
- Total: ( 1 + 5 + (3 \times 6) = 24 ) valence electrons.
- Determine the Basic Structure:
- Nitrogen is the central atom, and it forms single bonds with two oxygen atoms and a double bond with the third oxygen atom.
- The hydrogen is attached to one of the oxygen atoms.
- Place the Electrons:
- The oxygen atoms around nitrogen will follow the octet rule. Two of the oxygens will each have a single bond with nitrogen, while one oxygen will have a double bond with nitrogen.
- The oxygen with the single bond will carry a negative formal charge, and the nitrogen will have a positive formal charge.
- The oxygen with the double bond to nitrogen will have no formal charge, and the hydrogen is attached to the single-bonded oxygen.
- Formal Charges:
To calculate the formal charges:
- Formal charge = ( \text{Valence electrons} – \text{Nonbonding electrons} – \frac{\text{Bonding electrons}}{2} )
- Nitrogen has a formal charge of +1 because it has 4 electrons from bonding (instead of 5).
- One oxygen (with the single bond) has a formal charge of -1 (it has 7 electrons around it, instead of 6).
- The other oxygens and the hydrogen are neutral.
Formal Charge on Nitrogen:
The formal charge on nitrogen in the Lewis structure of HNO3 is +1.
This is because nitrogen, with 5 valence electrons, is involved in bonds that lead to only 4 electrons being associated with it (from the bonds), leading to a +1 formal charge.