Why is democritus's view of matter considered only an idea, while dalton's view is considered a theory?

Democritus's idea of matter doesn't relate atoms to a measurable property, while Dalton's theory can be tested through quantitative experimentation. Hope it helped :)

the atomic mass is the bottom number on the element.

-steel jelly

your answer is a. the enthalpy of formation for a pure element in its standard state is always positive.