Atomic

Structure

John Dalton’s

Atomic Theory

All Matter is Composed

of Tiny Particles Called

Atoms

1.

All Atoms of a Given

Element have Identical

Weights

2.

Atoms of One Element

Combine with Atoms of

Another Element in

Definate Proportions.

3.

Atoms are Indivisible in

Chemical Changes.

Atoms are not Created

nor Destroyed only

Rearranged

4.

J.J. Thomson

The electron

Ernest Rutherford

Gold Foil Experiment

Atomic Structure

James Chadwick

Credited with

the discovery

of the

neutron

MILIKAN’S OIL DROP EXPERIMENT

Millikan oil-drop

experiment, first direct

and compelling

measurement of the

electric charge of a

single electron.

Measured the

minute electric

charge that is present

on many of the droplets

in an oil mist.

IONS

Charged particles due to the loss or gain of electrons.

Metals: Lose electrons to form positive ions called cations. (ca+ions)

Non-metals: Gain electrons to form negative ions called anions.

A neutral atom of chlorine: Cl

17 protons (+) 17 electrons (-)

A chloride ion: Cl-

17 protons (+) 18 electrons (-)

CHLORINE ATOM CHLORIDE ION

WHICH PAIR REPRESENT

ISOTOPES?

A 12C, 12N

B 55Mn2+, 55Mn3+

C. 32S, 33S

WHICH PAIR REPRESENT

ISOTOPES?

A 12C, 12N

B 25Mn2+, 25Mn3+

C. 32S, 33S

WHICH PAIR HAVE THE SAME

NUMBER OF NEUTRONS?

A. 40Ca, 39K

B. 31P, 32P

C. 107Pd, 107Ag

WHICH PAIR HAVE THE SAME

NUMBER OF NEUTRONS?

A. 40Ca, 39K

B. 31P, 32P

C. 107Pd, 107Ag

SYMBOL e- Z A

n1

0

As-3

42

36 38 127

46 50 69

-I131

SYMBOL e- Z A

n1

0

As-3

36 33 75 42

Sr+2

36 38 127 89

Sn+4

46 50 119 69

-I131 54 53 131 78

Homework

Page 77 #6, 9, 11, 12, 17, 18, 23,

24, 28, 30, 33, 41, 47, 51, 53-57,

59, 114, 125

CP

Page 77 # 1-18, 22-32, 34, 36,

38, 42