Each pre-class Podia question is based on the pre-class material and working through the pre-class material will help you formulate your response. Consider the problem and write down/draw out your solution in your class notebook. These questions are designed to hone your skills so that you can analyze and solve mastery problems you will encounter throughout the course.
Two days before the next whole-class session, the pre-class Podia question will become visible in Podia, where you can click on the prompt and submit your answer.
Submissions for pre-class Podia activities are due 1 hour before the start of your whole-class. Be sure to submit your response before the due time.
Day 12 Pre-Class Podia Activity
Hydrogen azide has the following atom connectivity: H-N-N-N. Construct the best Lewis structure that you can for this molecule. (More than one “best” structure may be possible). Assign a hybridization (e.g., sp, sp2, sp3) to each N atom and label with “*” symbols any N atoms that have unhybridized p orbitals.
Based on your valence bond theory analysis, are electrons delocalized over two or more bonds of hydrogen azide? If so, sketch a series of resonance forms that illustrates the extent of this electron delocalization. How many electrons participate in the π-bond network of this molecule?
There are two measured N-N bond lengths: one N-N bond is measured to be 1.13 Å and the other N-N bond is measured to be 1.24 Å. Use the series of resonance structures you drew to determine which N-N bond in hydrogen azide corresponds to the shorter bond, and which corresponds to the longer bond. Connect your claims to your resonance structures using the data (average bond lengths of N-N bonds) provided below.
| Bond | mean (Å) | range (Å) |
| N-N | 1.52 ± .33 | 1.18 – 2.24 |
| N=N | 1.20 ± .06 | 1.14 – 1.25 |
| N≡N | 1.12 ± .02 | 1.10 – 1.13 |
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