CHEM 120: Exam 1 Scientific Experiments and their Conclusions

JJ Thomson

used a cathode ray tube to shock particles and discovered a negatively charged particle (the electron)

Robert Millikan

oil drop experiment, determined how much negative charge an electron has

Rutherford

A gold foil was hit with alpha particles, most particles went right through, while some bounced off, showing that atoms are mostly empty space with a concentration of positive charge in the NUCLEUS, this disproved the plum pudding model

Rutherford and Chadwick

neutrons

Proust

law of definite proportions, mass ratio is a property of a compound, every compound contains fixed and constant proportions of its constituent elements

Two-Slit Interference

light is passed through two slits, creates interference pattern of constructive and destructive interference, showing that light WAVE properties

Einstien photoelectric effect

shinned light on a metal, and if the light had a high enough frequency, it could bump an electron off the metal, shows that light has PARTICLE properties, particles of light are called photons

Photoelectric effect formula

Energy= plank's constant times frequency, or Energy= plank's constant x speed of light/wavelength (WAVELENGTH IS IN METERS 1 m/10^9 nm)

de Broglie

double slit experiment, shot electrons (small matter), high velocity through two slits and an interference pattern emerged, determined all matter has PARTICLE-WAVE DUALITY

Heisenberg uncertainty principle

impossible to know location and momentum of an electron at the same time, the more we know about one, the less we know about the other, SHOWS US THERE IS A LIMIT ON ABILITY TO MEASURE

Schrodinger

mathematically describes electron behavior, orbitals are based on mathematics to predict how things will interact