ASTRO 142 Chapter Notes - Chapter 4: Fermion, Transuranium Element, Inverse-Square Law
Document Summary
Antoine lavoisier and joseph priestley showed that it was possible to attribute chemical behaviors to certain substances into which most chemicals could be broken down. Each element corresponded to a unique type of particle (atom) Variety of chemicals created by chemical bonds between atoms. Combinations of two or more atoms are called compounds. Most important elements of astronomy are hydrogen and helium. Rutherford"s model (tightly packed positive nucleus surrounded by orbiting electrons) replaced the thomson plum pudding model (individual electrons embedded in a cake of positive charge) Electrostatic force between charges obeys an inverse square law. Doesn"t work as it was known that accelerated charged particles radiate away some of their energy in the form of light. Orbiting electrons should lose energy and spiral into nucleus. Atom with smallest atomic number (hydrogen) has a nucleus consisting of a single particle (proton) Electrons can occupy only discrete orbits of fixed energy. If electron occupied a permitted orbital it did not radiate.
