Chemistry
What we have learned so far
Matter
Anything that has mass and takes up space. There are three states of matter: Solid, liquid, gas.
Compound
A substance made up of atoms and different elements.
Pure Substances
Matter that has a fixed composition and define properties.
Homogenous
A mixture in which the composition is constant throughout. Also called a solution.
Greek Philosophers
Democritus: First person to propose the idea that matter was not infinitely divisible Aristotle: disagreed with Democritus because he did not believe empty space could exist. John Dalton: explained conservation of mass in reaction as the result of the combination, separation, or rearrangement of atoms.
Protons
Positive charged particles in the nucleus.
Atomic Numbers
The number of protons in the nucleus of an atom that identifies the element.