DemocritusLaw of Definite ______

Law of ______

Atomic Theory

All matter is comprised of atoms

Atoms are indivisible

Cathode Ray Tube Exp.

model

These can be lost or gained

e-/m ratio

Charge on the electron ________ Oil-Drop Exp.

Gold Foil Exp.

Atom is mostly…

Nucleons

Most are…

The AtomThe Atom

John Dalton

Compostion Conservation

Atoms of different elements have different masses

Atoms rearrange in chem rxtions

LaviosierProustJ. J. Thomson

The electron

(negatively charged matter)

1.76x108 C/g

Millikan’s

Plum Pudding

1.6x10-19 C

mass of e-

9.11x10-28 g

ions

Ernest Rutherford

Nucleus (positive, dense core)

empty

protons neutrons(+ charge) (no charge)

Chadwick

AZAtomic # Mass #

nuclideAXz

Element-A

A group of

isotopes Atomic masses

Weighted Averages

Mass Spec.

radioactive

AlphaB

eta

Gam

ma

matter

(Energy)

Equations to describe these

Ionizing radiation

Hard Little Spheres

Planetary Model

Chapter 3... HChem.

History

counting them

The MOLE

1 mole = 6.02 x 1023 = molar mass

Use D.A.

A particular atom

3H → 3He + ___

The decay of hydrogen-3The decay of hydrogen-3

1 2 0e- -1

(beta)(beta)

227Th → 4 + ____

The alpha decay of thorium-227The alpha decay of thorium-227

90 2 223Ra 88

When a sample of bromine atoms is injected into a mass spectrometer, the results obtained can be shown.

Mass Number

# o

f at

om

s

(ou

t o

f 10

000)

79 81

5069 4931

Use the data to compute the atomic mass of natural bromine. (The mass values for 79Br and 81Br are 78.92 amu and 80.92 amu respectively.)(0.5069)(78.92 amu) + (0.4931)(80.92 amu) =

79.91 amu

(50.69%) (49.31%)

Silver has two naturally occurring nuclides. One is silver-107 and the other silver-109. Knowing the atomic mass of silver is 107.9 amu, determine the relative abundance of each nuclide in a natural sample of silver if each nuclide has a relative atomic mass as given below:

silver-107 = 106.905 amu

silver-109 = 108.970 amu

X(106.905 amu) + (1-X)(108.970 amu) = 107.9 amu

106.905X amu + (108.970 amu - 108.970Xamu) = 107.9 amu

106.905X amu - 108.970X amu = 107.9 amu - 108.970 amu

-2.065X amu = -1.07 amu X = 0.518

Ag-107 = 51.8%

Ag-109 = 48.2%

A sample of silver has a mass of 4.97 grams. How many silver atoms are in the sample? Also, how many of those atoms have 60 neutrons?

4.97 g Ag 6.02 x 1023 atoms Ag

Remember that silver-107 is 51.8% of the silver atoms in a sample of silver.

1 107.9 g Ag= 2.77 x 1022 atoms Ag

(0.518)(2.77 x 1022 atoms silver) =

1.43 x 1022 atoms of 107AgThe test has:

•20 multiple choice

• 16 fill in the blank

• 2 problem solving

• 1 essay!!!!!