How did J. J. Thomson know there was a positively charged part of the atom? and How did Rutherford’s ‘Gold Foil Experiment’ prove that there was a nucleus?

What is a main difference between a mixture and a pure substance? a mixture is only a liquid, but a pure substance can be in any state.a mixture looks the same throughout, but a pure substance does not.1 a mixture can vary in composition, but a pure substance has a set composlo a mixture can be made up of a single compound, but a pure substance car