You probably don't want to get antonyms, since that would be too obvious. Also, what would the antonym of Hydrogen be?
You also don't want arbitrary word like "car" or "house", because that would also be too obvious and likely make the answer ridiculous.
You want kind of related words and perhaps even have a difficulty. Probably "Uranium" is simple to rule out, but "Oxygen" and "Nitrogen" would be difficult?
My experience on guessing games is: it takes a lot of thought and manual work to get good questions with enough wrong options to answer.
My recommendations for a guessing game:
- try to find more than one correct answer, otherwise players will remember it too easily. (Unfortunately sometimes there aren't)
- find a lot more incorrect answers than needed. I you display 3 incorrect answers on the screen, find at least 10 incorrect answers to choose from. This will take the players time to read and make it more fair for newcomers.
Overall you probably want a template engine for generating sentences and a "database" (JSON or whatever) to put your carefully crafted words in.
Sorry that I'm not suggesting a fancy AI algorithm for this task. How should the AI be able to figure out whether a valid (or invalid) selection for an atom is based on weight, binding energy, free electrons, radioactivity or other criteria?
I found that above is even true for math questions. Of course it's typically easier to find wrong answers. But you still want the number range to match certain criteria (like 1 to 10 for first grade school). How should an AI algorithm know you target a specific child age?