-
Joseph Priestley discovers oxygen; later, Antoine Lavoisier clarifies the nature of elements. Priestley produces oxygen in experiments and describes its role in combustion and respiration.
-
John Dalton provides a way of linking invisible atoms to measurable quantities like the volume of a gas or mass of a mineral. A theory that all matter is made up of tiny indivisible particles.
-
Humphry Davy uses an electric pile (what was a battery) to separate salts by a process now known as electrolysis.
-
Friedrich Woehler accidentaly synthesizes Urea frm materials to prove that substances made by living can be reproduced with nonliving substances.
-
Freidrich Kekule figures out the chemical structure of benzene, bringing the study of molecular structure to the forefront of chemistry. He writes that after years of studying the nature of carbon-carbon bonds. The structure solves the problem of how carbon atoms can bons with up to four other atoms at the same time
-
Gustav Kirchhoff and Robert Bunsen find that each element absorbs or emits lights as specific wavelengths
-
Dmitry Mendeleyev realizes that if all of the 63 known elements are arranged in order of increasing atomic weight, their properties are repeated according to certain periodic cycles
-
Marie and Pierre Curie discover and isolate radioactive materials. Emission of ionizing radiation or partivles caused by the spontanous disintegration of atomic nucleous
-
J.J. Thomson discovers te negative charge particles are smaller than atoms
-
Niels Bohr publishes his model of atomic structure in which electrons travel in specific orbits around the nucleus, and the chemical properties of an element are largely determined by the number of electrons in its atoms' outer orbits
