Yes, as far as we know he was the first to theorize about this, although he had no way of proving his theory. He came up with the word "atomos," which is Greek for indivisible. We honor him even today by using the word atom, which is derived from it.
It was the Greek philosopher Democritus who proposed the hypothesis that matter was composed of tiny indivisible particles. Democritus also wrote on mathematical topics like geometry. He was born in 460 B.C. and died in 370 B.C.
They both proposed the theory that all matter consists of atoms.
Democritus
That matter was made up of indivisible particles -Apex
John DaltonJohn Dalton
Around 400 BC Democritus a Greek philosopher theorized that everything was composed of small indivisible particles he called atoms or "atomos".
particles
John Dalton
Democritus, in the 5th century, proposed his version of atomism. States that all matter was composed of small indivisible particles called atoms.
It was the Greek philosopher Democritus who proposed the hypothesis that matter was composed of tiny indivisible particles. Democritus also wrote on mathematical topics like geometry. He was born in 460 B.C. and died in 370 B.C.
Leukippos and Democritus; possible also Mochus.
These philosophers were Leukippus and his disciple Democritus.
The Greek philosophers Leucippus and Democritus first theorized about atoms. In fact, that's who named them atoms.
They both proposed the theory that all matter consists of atoms.
Democritus believed that matter was made up of tiny, indivisible particles called atoms. These atoms were eternal and unchanging. Democritus also proposed that different physical properties and interactions among atoms resulted in the variety of substances we observe in the world.
Leucippus (450?-370? BC), was a Greek philosopher. He proposed the atomic theory of matter, that all matter is constituted of identical indivisible particles called atoms. This theory was further developed by his student, Democritus.
Democritus