2Blocked by aluminum foil
Beta
3Can pass through human skin
Gamma, Beta
5Has a mass number of 4
Alpha
6Has a mass number of 0
Gamma
8Blocked by a pieace of paper
Alpha
9Has the highest energy
Gamma
10Is a helium nucleus
Alpha
11Average Atomic Mass
Mass x Decimal Number of %, then add all of them
12Protons = Electrons
Neutral Atom
13Protons>Electrons
Positive Charge
Cation
14Protons<Electrons
Negative Charge
Anion
15How to get # of protons
atomic number
16How to get # electron
Same as protons except if there is a charge
17How to get # neutrons
mass-protons
18Democritus
He was the first to propose that matter was composed of small, indivisible particles called atoms
19Dalton
He developed the first complete atomic theory, stating that all matter is made of atoms, which are indivisible. All atoms of a given element are identical in mass and properties. Compounds are combinations of two or more different types of atoms
20J.J. Thomson
He discovered the electron and proposed the “plum pudding” model of the atom, which suggested that electrons were embedded in a positively charged "pudding"
21Millikan
He conducted the oil-drop experiment to determine the charge of an electron
22Rutherford
He discovered the nucleus of the atom and proposed a model where electrons orbit the nucleus
23Bohr
He improved upon Rutherford’s model by explaining that electrons move in fixed orbits around the nucleus
24Schrodinger
He developed the quantum mechanical model of the atom, which describes the behavior of electrons as waves
25Chadwick
He discovered the neutron, a particle in the nucleus with no charge9