Draw the Lewis Structure for NO3 and State its Molecular Geometry: Is it Polar or Nonpolar?

The Lewis structure for the nitrate ion (NO₃^–) can be drawn by following these steps:

1. Count the total number of valence electrons. Nitrogen (N) has 5 electrons, and each oxygen (O) has 6, so for three oxygens, it totals 18. Since it’s an ion with a -1 charge, we add one more electron, giving us a total of 24 valence electrons.
2. Place the nitrogen atom in the center as it is less electronegative, and attach the three oxygen atoms around it. Each oxygen will form a single bond with nitrogen, using 6 electrons (3 bonds), which leaves us with 18 electrons.
3. Distribute the remaining electrons to the oxygen atoms to satisfy the octet rule. Place 6 electrons (or 3 pairs) around each of the three oxygens, using 18 electrons total.
4. Adjust one of the oxygen bonds to a double bond with nitrogen to ensure that nitrogen also has an octet. This is typically done for one oxygen atom. Now, you have one N=O double bond and two N-O single bonds.
5. Lastly, the oxygen with the double bond has 4 electrons and the other oxygens have 6, resulting in a formal charge of 0 for nitrogen, 0 for the double-bonded oxygen, and -1 for the single bonded oxygen.

This gives us the completed Lewis structure for NO₃^–:

Now, regarding its molecular geometry, the nitrate ion has a trigonal planar geometry due to the three regions of electron density (the three N-O bonds) around the nitrogen atom.

As for its polarity, NO₃^– is a nonpolar molecule. This is because the electronegativity difference between nitrogen and oxygen is balanced out in the trigonal planar structure, causing the dipoles of the individual N-O bonds to cancel each other out.