1. A History of Atomic Theory
And
Structure

2. History of the Atom Not the history of atom, but the idea of
Original idea began Ancient Greece (400 B.C.E.)
Democritus - Greek philosopher ( BC)
Worked with his mentor Leucippus to develop first atomic theory.

3. History of Atom
Felt that had to be the smallest piece making up everything
For example: If you look at the beach...made of sand
Couldn’t you cut the sand into smaller sand? Eventually - no
Atomos - Greek for indivisible

4. Democritus’ (The Original) Atomic Theory
All matter consists of invisible particles called atoms.
Atoms are indestructible, solid - but invisible.
Atoms are homogenous (all one phase).
Atoms differ in size, shape, and arrangement.
For example:
Solids are made of small, pointy atoms.
Liquids are made of large, round atoms.
Oils are made of very fine, small atoms that can easily slip past each other.

5. Along comes another Greek
Aristotle - Famous philosopher
Said Democritus was wrong...
Said - All substances are made of 4 elements
Fire - Hot
Air - light
Earth - cool, heavy
Water - wet
Blend these in different proportions to get all substances

6. Who Was Right? Greek society was slave based
Felt that beneath Famous to work with hands
Means did not experiment
Greeks settled disagreements by debate
Aristotle was more famous
Therefore, he won
This caused people to ignore Democritus’ for more than years!
During that time was when alchemists came to be.

7. Law of Conservation of Matter (Mass)
Antione Lavosier
( )
Matter cannot be created or destroyed under normal conditions.

8. Joseph Proust ( )
Law of Definite Proportions (published not accepted until 1812) - compounds are made in a definite ration by mass
Law of Multiple Proportions - two compounds can be made by the same elements

9. John Dalton (1766-1844) English, public lecturer and teacher, 1803
Fun Fact - started teaching at the age of 12!
Summarized results of his experiments and those of other’s
Dalton’s Atomic Theory - combined ideas of elements with atoms

10. Dalton’s Atomic Theory
All matter is made of tiny indivisible particles called atoms.
Atoms of the same element are identical, those of different atoms are different.
Atoms of different elements combine in whole number ratios to form compounds
Chemical reactions involve the rearrangement of atoms.
No new atoms are created, destroyed, or subdivided.

11. Fun Facts about Dalton
When John Dalton died, 40,000 people attended his funeral procession.
He discovered color blindness
Still sometimes referred to as "Daltonism".
He was, himself, afflicted with color blindness.

12. Michael Faraday (1791-1867) English, 1832
Studied the effect of electricity on solutions
Coined the term electrolysis for splitting molecules with electricity
He was not a proponent of “atomism”

13. John Newlands (1837 - 1898) English, 1864 Very FIRST periodic table
Established the law of octaves,
elements are arranged according to increasing atomic weight
similar physical and chemical properties occur after each interval of seven elements.
John Newlands ( )

14. John Newlands
Newlands was one of the first to detect a pattern in properties of the elements
Fun Fact - Newlands had to petition for credit to be given for his work!
Text

15. Lothar Meyer (1830 - 1895) German, 1869
Contemporary of Mendeleev - created a PT at the same time.
His was not widely accepted.

16. Dmitri Mendeleev (1834-1907) Russian, 1869
Arranged elements into the first accepted periodic table.
Widely accepted because it was published in a textbook
Predicted missing elements
Determined that elements were a function of their atomic weights.
Became known as periodic law

17. Mendeleev’s Periodic Table

18. Sir William Crookes (1832-1919)
English, 1879
Discovered the properties of Cathode Ray Tube
Note: CRT was MADE by J. Plucker in 1859
Rays travel in straight lines from cathode
Causes glass to fluoresce
Deflected by electric and magnetic fields
The CRT is a vacuum tube with a voltage source flowing through it. (Pic next page)
FUN FACT: CRTs used to be our TVs

19. CRT
Voltage source - +
Vacuum tube
Metal Disks

20. GJ (George Johnstone) Stoney (1826-1911)
Irish, 1894
Proposed the idea of a negative particle existing
Wanted to call it the electron (DID NOT FIND IT)

21. Wilhelm Roentgen (1845-1923) German, 1895.
Found that very penetrating rays from CRT
Not were not deflected by magnetic field.
Named them X-rays

22. Henri Becquerel (1852-1908) French, 1896
Discovered radioactivity - he defined as spontaneous emission from a nucleus
By studying the effect of x-rays on photographic film

23. He proposed three types of radiation...
The real definitions came later...
Alpha
Positive Radiation - High speed helium nucleus
Beta
Negative Radiation - High Speed electron
Gamma
Neutral Radiation - High Energy radiation

24. J.J. (Joseph John) Thomson (1856-1940)
English physicist, 1897
Used CRT to discover the electron
Did so by finding the charge to mass ratio
He was also the first person to notice that the atom can be divided (First person to actually do it - not him)

25. Thomson’s Experiment
Voltage source - +

26. Thomson’s Experiment
Voltage source - +

27. Thomson’s Experiment
Voltage source - +

28. - + Thomson’s Experiment
Voltage source - +
Passing an electric current makes a beam appear to move from the negative to the positive end

29. - + Thomson’s Experiment
Voltage source - +
Passing an electric current makes a beam appear to move from the negative to the positive end

30. - + Thomson’s Experiment
Voltage source - +
Passing an electric current makes a beam appear to move from the negative to the positive end

31. - + Thomson’s Experiment
Voltage source - +
Passing an electric current makes a beam appear to move from the negative to the positive end

32. By adding an electric field
Thomson’s Experiment
Voltage source
By adding an electric field

33. By adding an electric field
Thomson’s Experiment
Voltage source + -
By adding an electric field

34. By adding an electric field
Thomson’s Experiment
Voltage source + -
By adding an electric field

35. By adding an electric field
Thomson’s Experiment
Voltage source + -
By adding an electric field

36. By adding an electric field
Thomson’s Experiment
Voltage source + -
By adding an electric field

37. By adding an electric field
Thomson’s Experiment
Voltage source + -
By adding an electric field

38. Thomson’s Experiment
Voltage source + -
By adding an electric field he found that the moving pieces were negative

39. Thomson’s Experiment 1904, Said the atom was like plum pudding
Called the ‘Plum Pudding Model’ of the atom
A bunch of positive stuff, with the electrons able to be removed

40. Marie Curie & Pierre Curie (1867-1934) (1859-1906)
Polish & French, 1898
Studied Uranium and Thorium and called their spontaneous decay process ‘radioactivity’
She and Pierre, husband, also discovered Polonium and Radium
Fun Fact: While she died of illness, her husband was run over by a horse drawn cart. He slipped while crossing the street in the rain.

41. Ernest Rutherford (1871-1937) New Zealand, 1898
Studied radiation and labeled them alpha and beta radiation. (need to know for future experiment)

42. Frederick Soddy (1877-1956) English, 1903
Proposed the idea of isotopes
Discovered half-life

43. Max Planck (1858-1947) German, 1900 Developed the idea of ‘quanta’
packets of energy

44. Richard Abegg (1869-1910) German, 1904
Discovered the inertness of Nobel Gases because of their stable electron configuration
Fun Fact - Actually died at the age of 41, in a balloon crash

45. Albert Einstein (1879-1955) German, 1905
Explains the photoelectric effect
Electrons are emitted from matter when they absorb energy from light.
Developed E=mc2

46. Hans Geiger ( )
German, 1906
Developed an electrical ‘clicker’ to register alpha emission
Called a Geiger Counter

47. Lise Meitner & Otto Hahn (1878-1968) (1879-1968)
Lise Meitner - Austrian
Otto Hahn - German
1907, Worked together to discover that Uranium can cause nuclear fission
without them we would not have nuclear power (and the world may never have experienced the nuclear bomb.)

48. Robert Millikan (1868-1953) American, 1909 Oil Drop Experiment
Determined the charge and the mass of an electron

49. Geiger - Again
1909, Developed an experiment called the foil experiment
discovered large angle deflections of alpha particles by thin metal foils
Alpha particles - positively charged pieces given off by uranium
Shot them at gold foil which can be made a few atoms thick

50. Florescent
Screen
Lead block
Uranium
Gold Foil

51. What he expected

52. What he got

53. Rutherford - Again Ernest Rutherford English physicist.
Fun Fact - he had 11 siblings!
Believed in the plum pudding model of the atom.
He interpreted the results of Geiger (1909) that showed that there must be a small dense core at the center of the atom.
Thus disproving plum pudding

54. +

55. How he explained it + Atom is mostly empty
Small dense, positive piece at center
Alpha particles are deflected by it if they get close enough +

56. Nucleus Theory The atom is mostly empty space Two regions Nucleus
Surrounded by electrons
Called Nuclear Model

57. Rutherford - Again 1914, suggests the ideas of protons in the nucleus
Rutherford coins the term proton.

58. Henry Moseley (1887-1915) 1914, Determined the charges on nucleus
Called this atomic number
Used this to reorganize the periodic table based on atomic number
Fun Fact: Died at the age of 27 during WWI
Periodic Table Song

59. Neils Bohr ( )
(HONORS WILL DISCUSS IN DEPTH) Bright line spectrum
Tried to explain presence of specific colors in hydrogen's spectrum
Energy levels
Electrons can only exist in specific energy states
Ground State
Excited State
Developed planetary model
electrons moved in circular orbits with specific energy levels

60. Louis de Broglie ( )
1923, Discovered that electrons have a dual nature - similar to particle and waves.
Supported work done by Einstein.

61. Gilbert N. Lewis (1875-1946) Introduces the term photon
quanta of light

62. Edwin Schrodinger ( )
Quantum Mechanical Model (modern day model)
Electrons are in probability zones called orbitals not orbits and the location cannot be pinpointed
Electrons are particles and waves at same time (using de Broglie)
Developed quantum numbers based on theories of Albert Einstein and Max Planck (HONORS)

63. Werner Heisenberg (1901-1976) 1927, Heisenberg Uncertainty Principle
You cannot know the velocity and position of a particle at the same time.

64. Friedrich Hund (1896-1997) Robert Milliken (1868-1953)
German & American, 1928
HONORS ONLY - Introduce concept of molecular orbitals

65. James Chadwick (1891-1974) 1932 - Discovered neutrons
Combined his work and others work - found that there was more mass in the nucleus than the proton
Neutral particles in nucleus of an atom - mass close to proton
Fun Fact - Student of Rutherford and Rutherford was a student of Thomson

66. Werner Heisenberg - Again (1901-1976)
German, 1932
Revised Electron Cloud Model to include Neutrons
Uses it to explain isotopes

67. Enrico Fermi (1901-1954) Italian, 1934
Uses beta decay to produces neutrinos
no charge, subatomic particle
extremely tiny mass.
mass has never been measured accurately.

68. Carl Anderson (1905-1991) American, 1936 Discovers muon
subatomic particle
207 x bigger than the electron
same charge

69. Atomic Bomb Actually began in 1919 with Rutherford
Ernest Rutherford, Albert Einstein, and Niels Bohr regarded particle bombardment as useful in furthering knowledge but “unlikely to meet public expectations of harnessing the power of the atom for practical purposes anytime in the near future.”

70. Einstein’s Letter to FDR
1939, FDR and advisors met to review Einstein’s letter
“recent research on chain reactions utilizing uranium made it probable that large amounts of power could be produced by a chain reaction and that, by harnessing this power, the construction of "extremely powerful bombs..." (was conceivable.)
Roosevelt became convinced of the value of exploring atomic energy.

71. Manhattan Project 1939, epic, secret, wartime (WWII) effort
Design and build the world's first nuclear weapon.
Used efforts of the world's greatest physicists and mathematicians
Cost $20 billion (2 billion at the time)

72. Manhattan Project
Over 90% of the cost was for building factories and producing materials
less than 10% for development and production of the weapons.
Grew to employ more than 130k people
Note: Considerable controversy surrounds Heisenberg’s work for the German’s on atomic research during World War II.

73. Manhattan Project Driven by fear of Hitler's Germany
Monumental project - but took less than four years
Fission chain reaction from U and Pu that released the bombs' destructive energy.
United States exploded a nuclear bomb over Hiroshima on August 6, 1945.

74. Murray Gell-Mann (1929 - present)
Fun Fact: Entered Yale at the age of 15!
1964, Coined the term “quark”
Quark = fast moving point of energy (every p and n are made up of three)
The quark makes up the neutrons and protons in the nucleus
It can never be isolated
There are up quarks and down quarks
They are 10-15mm in size
1969, awarded the Nobel prize in Physics for his contributions

75. Common Particles Proton - previous slide Neutron - previous slide
Electron - previous slide
you should know that the charge of proton and electron are not +1 and - 1
aka – Fermion
Muon – 200x bigger than an electorn, negative charge
Quark - previous slide
Boson - particle with no spin, may be any number of particles in the same state.

76. Hadron Collider
Hadron - composite particle made up of quarks held together by a strong force.
CERN (European Organization for Nuclear Research) - located in Geneva, Switzerland

77. Hadron Collider Searching for Higgs boson particle (theorized in 1964)
CERN announces discovery of a new particle with properties consistent with Higgs boson after experiments
The HB Particle has been referred to as the God particle
B/c it makes up all mass