Plum pudding “chocolate chip cookie” model- The positive mass was dotted, the negatively charged electrons.
Gold Foil Experiment-
Observations- 1.) Most of the particles go straight through the foil. 2.) A few particles were deflected straight back. 3.)Some were slightly deflected.
Conclusions- 1.) Atoms must be mostly empty space. 2.) Small dense center later called nucleus. 3.) Nucleus must be positively charged since alpha particles are positive.
Oil Drop Experiment- The oil-drop experiment was an experiment performed by Robert Millikan and Harvey Fletcher in 1909 to measure the elementary electric charge (the charge of the electron).
Conclusion- The mass of 1 electron is 1/1840 the mass of a proton essentially the electron has no mass.
Dalton’s Atomic Theory- 1.) Matter is composed of tiny, indivisible particles known as atoms (protons, neutrons and electrons.) 2.) Atoms of the same element are identical, and atoms of any one element are different from those of another element. 3.) Reactions occur when atoms are separated from one another, joined, or rearranged, but matter cannot be created or destroyed. 4.) Atoms of different elements can combine in whole number ratios to form compounds.
Law of Definite Proportion- Use water to identify the ratios: ratio of atoms, ratio of moles, ratio of %, ratio of mass.
Law of Multiple Proportion- With the same set of elements More Than One compound can be formed. Each compound can be formed. Each compound has a specific recipe. Ex. gasoline (types) gold rings (14k, 18k, 24k).