Question

which scientists law about the ratios of masses of elements in a compound did john daltons work on the atomic structure help to explain?
democritus
j.j. thomson
ernest rutherford
joseph proust

Explanation:

John Dalton's work on the atomic structure was based on the concept of atoms as the fundamental building blocks of matter. Joseph Proust's law (Law of Definite Proportions) states that a given chemical compound always contains its component elements in fixed ratio (by mass) and does not depend on its source and method of preparation. Dalton's atomic theory (which considered atoms as indivisible particles at that time) along with Proust's law helped in understanding the ratios of elements in a compound. Ernest Rutherford discovered the nucleus. J.J. Thomson discovered the electron. Democritus was a Greek philosopher who proposed the concept of atoms but not in the scientific - law - based way related to compound composition ratios.

Answer:

Joseph Proust