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The Alchemists devoted untold grueling hours to transmute metals into gold. The Alchemists where not an instant success. -
Plato theorized that solid forms of matter are composed of elements. -
Democritus theorized that all material bodies are made up of indivisibly small atoms. -
Antone Lavoisier determined that oxygen was a key substance in combustion, and he gave the element its name. -
Avogadro studied the properties of electricity and liquids, but his best known work was with gases. It was known by 1809 that all gases, when heated equally, expand by the same amount. -
He introduced the atomic theory into chemistry and for his work on human optics. He discovered all matter is made of atoms. -
Dmitri Ivanovich Mendeleev was a Russian chemist and inventor. He is best known for formulating the Periodic Law and creating a version of the periodic table of elements. -
He discovered a systematic mathematical relationship between the wavelengths of the X-rays produced and the atomic numbers of the metals that were used as the targets in X-ray tubes. -
He achieved an original study of cathode rays culminating in the discovery of the electron, which was announced during the course of his evening lecture to the Royal Institution. -
Pierre and Marie Curie discovered the existence of the elements radium and polonium. -
He mathematically proved the existence of atoms. -
He successfully determined the magnitude of the electrons. -
He established that the mass of the atom is concentrated in its nucleus. -
Neils Bohr proposed a model of the atom in which the electron was able to occupy only certain orbits around the nucleus. -
he proved the existence of neutrons- elementary particles devoid of any electrical change. -
He discovered that the volume of a gas decreases with increasing pressure and vice versa.