The chemical formula for ammonia is NH3. Which of the following models could be used to represent ammonia?

To represent ammonia (NH3), you would typically look for a model that shows one nitrogen (N) atom bonded to three hydrogen (H) atoms. In a simple representation:

- The black dot could represent the nitrogen atom (N).
- The three yellow dots would represent the three hydrogen atoms (H).

If A. is described as one black dot with 3 yellow dots, this could be a valid representation of ammonia, showing the nitrogen atom in the center with the three hydrogen atoms surrounding it.

However, keep in mind that ammonia has a trigonal pyramidal molecular geometry due to the lone pair of electrons on the nitrogen atom, which isn't represented in a simple dot model. A more advanced model might show the three hydrogen atoms arranged in a pyramid shape around the nitrogen atom.

If you have more options or images to consider, feel free to share, and I can help you analyze them further!