Chemistry

Front 1

Democritus

Back 1

400 B.C.; the world is composed of 2 things: 1. atoms 2. empty space

Front 2

Dalton's Atomic Theory

Back 2

1.All atoms are composed of tiny particles called atoms
2.Atoms of the same elements are identical to each other and atoms of different elements are different
3.Atoms of different elements can mix together or chemically combine with each other in whole number ratio to form compounds
4.Chemical reactions occur when atoms are seperated, joined or rearranged (atoms of one element cannot change into another)

Front 3

Electrons

Back 3

negatively charged subatomic particles (J. J. Thompson)

Front 4

Cathode Ray

Back 4

a stream of electrons produced at the negative electrode (cathode) of a tube containing a gas at low pressure

Front 5

Cathode

Back 5

negatively charged

Front 6

Anode

Back 6

positively charged

Front 7

Robert A. Milikin

Back 7

discovered the quanity charge carried by an electron

Front 8

Protons

Back 8

postively charged subatomic particles (Goldstein)

Front 9

Neutrons

Back 9

subatomic particles with no charge but with a mass nearly equal to that of a proton (Chadwick)

Front 10

Gold Foil Experiment

Back 10

Rutherford

Front 11

Atomic Number

Back 11

is the number of protons in the nucleus of an atom of that element

Front 12

Mass Number

Back 12

total number of protons and neutrons in an atom

Front 13

How can you find the number of neutrons?

Back 13

# of neutrons=
mass # - atomic #

Front 14

Isotopes

Back 14

atoms of the same element that have the same atomic number but different atomic masses due to a different number of neutrons

Front 15

Atomic Mass

Back 15

a weighted average mass of the atoms in a naturally occuring sample of the element