CHEM 1A Chapter Notes - Chapter 2: Unified Atomic Mass Unit, Ernest Rutherford, Weighted Arithmetic Mean
Document Summary
Early ideas about the building blocks of matter (p. 47) Modern atomic theory and the laws that led to it (p. 47) Subatomic particles: protons, neutrons, and electrons in atoms (p. 56) Finding patterns: the periodic law and the periodic table (p. 61) Atomic mass: the average mass of an element"s atoms (p. 66) Molar mass: counting atoms by weighing them (p. 70) Each element is composed of indestructible particles called atoms. All atoms of a given element have the same mass and other properties. Atoms combine in simple, whole-number ratios to form compounds. Atoms of one element cannot change into atoms of another element. In a chemical reaction, atoms change the way that they are bound together with other atoms to form a new substance: the electron (2. 4) C. 1: j. thomson discovered the electron in the late 1800s through experiments with cathode rays. He deduced that electrons are negatively charged, and he measured their charge-to-mass ratio.
