 History of the “Atomic Theory” video
 alchemy- primarily trying to make gold
 fire, water, air, Earth
 early “atomists” were considered Godless
 for 1600 years, the idea of the atom was not accepted
 a French guy said God made atoms so then everyone was happy
 this allowed scientists to begin their learning of the atom/elements

 is made up of tiny particles called atoms
 first evidence for atoms was called Brownian motion for Robert Brown, who first noticed the jerky motion of pollen grains in water

Matter
Are all the particles alike?
YES NO
Pure Substance
Are the particles one kind of atom?
YES NO
Element Compounds or Molecules
Mixture
Are the particles well-mixed and mixed evenly?
YES NO
Homogeneous
Mixture
Heterogeneous
Mixture

Conclusion for lab.
This way of categorizing better, your way better, or both are good and why??

1.
Elements
 all particles are alike
 the smallest particle of an element that is still recognizable is called an atom
 they can’t be broken down anymore by “normal means”
 they are found on the periodic table
 currently there are about 118 elements

chemical symbols are used to represent the elements
• Example: C=carbon, N=nitrogen…..

2.
Compounds and Molecules (over 10 million exist)
 two or more elements chemically combined
 once combined, the properties of a compound are different than the elements that make it up
 can be broken down into the elements that make them up
 example: Sugar is C
6
H
12
O
6
 made up of carbon, hydrogen, and oxygen
 looks nothing like C, H, O by themselves

1.
Heterogeneous Mixture
 different samples are not necessarily made up of exactly the same proportions of matter
 can often see different particles mixed together
 often can be easily separated

2.
Homogeneous Mixture
 is the same throughout
 often can’t see different particles mixed together
 often difficult to separate
 examples: steel, milk, salt water, Kool Aid®