Which best describes how Dalton's early theory of atomic structure differs with modern theories? He did not know -

John Dalton introduced a theory proposing that elements vary because of the mass of their atoms.

He said in his theory that all matter is made up of indivisible blocks called atoms. He also stipulated in his theory that elements are identical thus, have different sizes and masses.

Dalton's theory was different from Niels Bohr who proposed a new atomic model which was also commonly known as the modern atomic theory. Bohr's theory says that atoms are arranged in circular orbits around the nucleus. He patterned his model as the solar system.