Some of the scientists involved in discovering the atoms were John Dalton, J.J Thomas, Ernest Rutherford, Niels Bohr and Erwin Schödinger.
John Dalton recognized that atoms from a particular element differ from atoms and he came up with the Solid Sphere Model.
J.J Thomas recognized electrons as compounds of atoms and he came up with the plum pudding model.
Ernest Rutherford recognized that positive charge was located in the middle of the atom in the nucleus and he came up with the nuclear model.
Niels Bohr proposed stable electron orbit and explained the emission spectra of the elements. Besides, he came up with the planetary model.
Erwin Schödinger showed that electrons do not move in orbits around the nucleus but in clouds where their position is uncertain and he came up with the quantum model.
Hope that helps!
