Indivisible The Atomic Theory

If we simply look at matter, even under a microscope, it is not obvious that matter is composed of tiny particles. In fact, it appears to be just the opposite. If we divide a sample of matter into smaller and smaller pieces, it seems that we could divide it forever. From our perspective, matter seems continuous. The first people recorded as thinking otherwise were Leucippus (fifth century B.c., exact dates unknown) and Democritus (460-370 b.c.). These Greek philosophers theorized that matter was ultimately composed of small, indivisible particles. Democritus suggested that if you divided matter into smaller and smaller pieces, you would eventually end up with tiny, indestructible particles called atomos, or atoms, meaning indivisible.  

The ideas of Leucippus and Democritus were not widely accepted, and it was not until 1808—over 2000 years later—that John Dalton formalized a theory of atoms that gained broad acceptance. Dalton s atomic theory has three parts  

Each element is composed of tiny indestructible particles called atoms. 

All atoms of a given element have the same mass and other properties that distinguish them from the atoms of other elements. 

Atoms combine in simple, whole-number ratios to form compounds. 

---