Indigo has the chemical formula C₁₆H₁₀N₂O₂. To find the number of atoms in a molecule of indigo, we simply add the subscripts of each element:

* Carbon (C): 16 atoms

* Hydrogen (H): 10 atoms

* Nitrogen (N): 2 atoms

* Oxygen (O): 2 atoms

Total: 16 + 10 + 2 + 2 = 30 atoms

Therefore, there are 30 atoms in a molecule of indigo.