L-tryptophan zwitterion 3D Model — CAS 73-22-3

L-tryptophan zwitterion (C11H12N2O2, CAS 73-22-3) — a free educational 3D molecular model for teachers and students, by MolGod.org. Each atom is labelled with its own engraved element symbol: no colour chart needed. At its heart, L-tryptophan zwitterion is built around two rings (one 5-membered and one 6-membered), fused along a shared edge, both aromatic. The model shows 28 bonds: 17 single, 1 double and 10 aromatic, drawn in Kekulé form. How many atoms can the class find? The engraved spheres give 11 C + 12 H + 2 N + 2 O, so the answer should be 27. Functional groups to find on the model: carboxylic acid group (-COOH) and primary amino group (-NH2). Full record and more free models: https://molgod.org/molecule/73-22-3/?utm_source=sketchfab&utm_medium=referral&utm_campaign=edu-3d-models Licence & provenance: https://molgod.org/licenses/stl/73-22-3/ Required attribution (CC BY-SA 4.0): "L-tryptophan zwitterion 3D model by MolGod.org — https://molgod.org/molecule/73-22-3/ — CC BY-SA 4.0"