Chem Chapter 3
Terms
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- Democritus
- said that all things contain matter and matter is made up of atoms and void, he also said that atoms are undivideable
- Dalton Theory
- he defined the atom having a uniformed density and being indivisible
- Law of conservation of mass
- matter/mass is neither created or destroyed by physical or chemical changes
- Law of definite proportions
- no matter the size of a sample, a chemical compound contains the same proportion % elements by mass
- Law of Multiple Proportions
- the same elements can combine in different rations to form different compounds
- Avagardo's Number
- the number of particles in one mole of a pure substance
- Atomic Number
- the # of protons in the nucleus for each atom of that element
- Mass Number
- total # of protons and neutrons
- isotopes
- are atoms of the same element that have different masses
- Millikan
- found out that electrons carrynegative electrical charges
- Chadwick
- discovered the neutron which he found to have no charge and wieghed roughly the same as the proton
- Average Atomic Mass
- is the weighted average of the atomic masses of the naturally occuring isotopes of an element