1. Chemistry Chapter 4 – Atomic Structure
Video Clip: The Elements: Forged in Stars
Video Clip: The Origin of the Elements

2. Original Thoughts
The Greek thinker Aristotle classified the fundamental elements as fire, air, earth, and water.
The ancient Chinese believed that the five basic components of the physical universe were earth, wood, metal, fire, and water. Pinyin, Wu Xing
In India, 3rd century AD the five gross elements were claimed to be space, air, fire, water, and earth. Samkhya-karikas by Ishvarakrsna

3. Democritus Greek philosopher 400BC
First to suggest the existence of atoms
Atoms: smallest particle of an element that retains its identity
Democritus could not support his ideas or answer the question what holds everything together so his concept was dismissed.

4. John Dalton English Chemist early 1800’s Dalton’s Atomic Theory
All elements are composed of tiny indivisible particles called atoms
Atoms of the same element are identical.
The atoms of one element are different than atoms of other elements.
Atoms of different elements can physically mix together or chemically combine in whole # ratios to form compounds.
Chemical reactions occur when atoms are separated, joined, or rearranged.

5. Eugen Goldstein German physicist
In1886 discovered positive particles by observing canal rays in a cathode ray tube filled with hydrogen gas

6. Thomson’s Atomic Model
Plum Pudding
JJ Thomson
British physicist
Found the electron in 1897 using cathode-ray tube experiments
Negatively charged electrons in an atom were floating (or moving) in a sea of positive charge
Plum Pudding Model established1904
Cathode Ray Tube

7. Ernest Rutherford New Zealand-born British chemist and physicist
Found the nucleus 1911
Gold Foil Experiment
He stated that the atom was a lot of empty space with a small, dense nucleus
Rutherford’s
Atomic Model

8. Moving past Rutherford
Niels Bohr’s Model
Danish Chemist
Particle theory
e- travel in circular orbits called energy levels
Each orbit has a quantized energy
Looked at line spectra
Important Vocabulary
Energy Level: fixed energy of an e-
Quantum: amount of energy required to move from one energy level to the next
De Broglie Model
French Chemist
Wave theory
Similar to Bohr’s model, but e- act as waves not particles.

9. Erwin Schrödinger Werner Heisenberg
Electron Cloud Atomic Model
Erwin Schrödinger
Austrian Physicist
Father of Quantum Mechanics
Used mathematical equations to describe the location of the e-.
Werner Heisenberg
German theoretical Physicist
Awarded the 1932 Nobel Prize in Physics for the creation of quantum mechanics
Can’t know position and momentum of an e- at the same time.
e- don’t move in defined orbits

10. James Chadwick English physicist 1891-1974
In 1932 tracked particle emission from radioactive elements and discovered a particle with no charge: the neutron
Explained why atomic mass and atomic # differed

11. The Changing Model of the Atom
Democritus
Dalton
Thomson Plum Pudding
Rutherford
Nuclear Atom
De Broglie – Wave Model
Bohr Model
Electron Cloud Model

12. The Atom Song

13. The subatomic particles summary
Electrons have such a small mass compared to protons and neutrons we say electrons have no mass – but really they do.
Subatomic Particle
Location
Charge
Relative Mass (amu)
Actual Mass (g)
Electron (e-)
e-cloud/ orbital
Negative
(1/1836)
9.11 x
Proton (p+)
nucleus
Positive 1
1.67 x
Neutron (n0)
neutral
(amu – atomic mass unit 1/12 of a Carbon-12 atom)

14. Isotopes Atoms of the same element can have different masses
Isotopes: atoms with the same # of p+, but different #s of n0, and different masses
Its like different flavors of each element
Atoms with a too few or too many neutrons can exist for a while but can be unstable or radioactive
The Nuclei of the 3 isotopes of Hydrogen

15. Comparing Isotopes Same: Different: Element (Lithium) Atomic # (3)
# of p+ (3)
# of e- (3)
Different:
Mass # (6, 7, 8)
# of n0 (3, 4, 5)

16. Ions Ions: charged particles (+ or -) cations (X+) positive ions
Form when an atom or molecule gains or loses e-
cations (X+) positive ions
anions (X–) negative ions
To calculate the charge of an ion
Compare the p+ & e-
Charge = p+ – e-

17. Always the smaller #
Always a whole # (no decimals)
= number p+
Always the BIGGER #
Usually a decimal
= # p+ & n0

18. Symbols x
Mass #
Charge
Atomic #

19. Atoms: by the NUMBERS
Atomic #: unique for each element; gives elements their identity
= # of p+
Mass #: whole # mass for a specific isotope; often written after element name (Krypton-84)
= # of p+ + # of n0
Atomic Mass: weighted average mass of all isotopes of an element
recorded as a decimal on the PT (periodic table)

20. Atoms: by the NUMBERS Protons = Atomic #
Atomic Mass
Protons = Atomic #
change the #p+ change the element
Neutrons = Mass # – Atomic #
Electrons = # of p+ (for Atoms)
For IONS: electrons = p+ - charge

22. The Standard Model Types of Particles:
Video Clip: CERN: The Standard Model of Particle Physics
Types of Particles:
Quarks
Leptons
Electron Tau
Muon Neutrinos
Bosons: (force particles)
Gluon Graviton
photon (EM) Higgs
strong force weak force
Particles were organized by spin, charge, mass, and lifetime

23. Video Clip: Quarks: Inside the Atom
Murray Gell-Mann found the name "quark" in the book “Finnegan's Wake" by James Joyce. The line "Three quarks for Muster Mark..." Gell-Mann received the 1969 Nobel Prize for his work in classifying elementary particles.
Video Clip: Quarks: Inside the Atom
6 Types of Quarks:
Up & Down
Top & Bottom
Charm & Strange

24. Finding the Quark
Fermilab – National Particle Accelerator Lab Chicago IL

25. HADRONS Video Clip: Understanding the Standard Model
Hadrons: particles composed of quarks
Baryons
Made of 3 quarks
Protons & Neutrons are types of Baryons
Mesons
Made of 2 quarks
(1 quark & 1 antiquark)