CHEM 1R03 Lecture Notes - Lecture 28: Quantum Mechanics, Alpha Particle, Vacuum Tube
27 Apr 2018
School
Department
Course
Professor
Chemistry Lecture Twenty-Eight
Atomic Theory
•Neil's Bohr: published atomic structure and electron configurations
•Erin Schrodinger: laid foundation of quantum wave mechanics
•JJ Thomson: investigated beams emitted by a cathode-ray vacuum tube, he
determined that the ray was made of tiny negatively charged particles which are
called electrons
•Thomson stated that atoms are breakable since they are made up of particles and
that atoms have a structure to them
•If you can break something up, it means it has structure
•Electrons are suspended in a positively charged electric field
•They also are tiny, negatively charged particles which are very light compared to
the mass of an atom (1/1836th mass of a hydrogen atom)
•Electrons also move very rapidly within the atom
•Rutherford assumed the atom was mostly empty space
•His experiment consisted of a gold foil where he used very thin sheets of target and
shot particles at it
•He also used very small particles as a bullet with high energy —> many passed
right through (roughly 98%)
•2% of the alpha particles that did not go through were deflected by large angles
•About 0.01% of the particles also bounced off the gold foil sheet
