Dalton’s Atomic Theory

The Scanning Tunneling Electron Microscope

Particle Accelerator

The Cathode Ray Tube

The Plum Pudding Model

Ernest Rutherford

The Gold Foil Experiment

The Gold Foil Experiment

Rutherford’s Gold Foil

The Gold Foil Experiment

Relative Abundance

• On earth, 99.759% of all naturally occurring oxygen is oxygen-16. Two other oxygen isotopes are found in small amounts: oxygen-17 (0.037%) and oxygen-18 (0.204%). Find the average atomic mass of oxygen.

• Element X has two natural isotopes. The isotope with a mass of 10.012 amu (10X) has a relative abundance of 19.91%. The isotope with a mass of 11.009 amu (11X) has a relative abundance of 80.09%. Calculate the average atomic mass of this element.