CHEM 1201 Lecture Notes - Chlorine, Scanning Tunneling Microscope, Chemical Formula
Document Summary
Ancient greeks were the first to postulate that matter consists of individual particles called. Plato and aristotle proposed that there can be ultimately no indivisible particles. John dalton"s - atomic theory (1803 - 1807) ~ D alton"s postulates: all matter is composed of tiny particles called atoms, all atoms of a given element have identical chemical properties. Atoms of different elements have distinct properties: in chemical reactions, atoms of an element are not changed into different types of atoms; instead, a chemical reaction changes the way atoms are combined. Atoms are neither created nor destroyed: atoms form chemical compounds by combining in whole-number ratios. All samples of a pure compound have the same combination of atoms. Atomic structure: atoms are composed of three fundamental subatomic particles: protons, neutrons, & electrons. The nucleus of an atom, which is very small, contains all of the protons and neutrons. It contains the majority of the mass of an atom.