What does gravitation force do in the atom?

Answer 1

Essentially nothing. Gravity is a very weak force, which only becomes measurable with large masses and over large distances. The other forces such as the "Strong Nuclear Force" are more energetic, but over only atomic distances. The "Weak Nuclear Force" and the "electromagnetic force" (which have been theoretically "unified" as the "electro-weak force" are weaker than the Strong Nuclear Force, but still far stronger than gravity - but electromagnetism is also effective only over fairly limited distances. Even VERY strong magnetic fields have very tiny effects over distances of hundreds or thousands of miles.

Gravity is effective over interstellar, even intergalactic distances, but it plays essentially no role at all at atomic distances.

Answer 2

Yes, though it is so minute on those levels compared to other forces that it cannot be noticed.