Why is dalton credited with proposing the first atomic theory if democritus was talking about atoms almost 2,200 years earlier?

Dalton was credited with suggesting the first atomic theory even if Democritus was talking about the atoms about 2000 years ago because Democritus ideas were not encouraged by any kind of proof. On the other hand, the theory given by Dalton was the first scientific theory as it was dependent upon the processes of scientific investigations. The theory given by Dalton was encouraged by repeated investigations and proofs.

it is stable as it is in group 0 which have full outer shells of electrons