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Introduction to Atoms

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Title: Introduction to Atoms


1
Introduction to Atoms
  • Chapter 4

2
Development of the Atomic Theory
  • Section 1
  • Page 80

3
Atom
  • The smallest particle in which a element can be
    divided and still be the same substance

Oxygen
4
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5
Theory
  • A unifying example for a broad range of hypothesis

6
Democritus Proposes the Atom
  • uncutable particle
  • Called it Atom meaning indivisible

7
Atoms
                                                                  
Stone Fur
8
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9
Democritus Atom
  • Small hard particles
  • Made of a single material (different shape
    size)
  • Always Moving
  • From different material by joining together

10
Aristotle Disagrees
  • Greek Philosophical
  • You would never end up with a indivisible particle

11
Dalton
  • Knew elements combine in specific proportions
  • But Why?

12
Dalton
  • Completed many experiments and concluded
  • specific proportions are do to atoms

13
Daltons Theory
  • All substances are made of Atoms
  • Atoms can not be divide, created or destroyed
  • Atoms of the same element are alike
  • Atoms join with other atoms to make new substancs

14
Dalton Close but not Prefect
  • New research produced new question concerning
    Dalton theory

15
Thomason electron
16
http//www.chem.uiuc.edu/clcwebsite/cathode.html
17
Negative Corpuscles
  • Corpuscles are negatively charge and now called
    electrons

18
Plum Pudding
19
Ernest Rutherford
  • Designed a experiment to test Thomsons theory on
    the structure of an atom

20
http//www.mhhe.com/physsci/chemistry/essentialche
mistry/flash/ruther14.swf
21
Ernest Rutherford
  • Positive charged Nucleus
  • Nucleus is majority of the atoms mass
  • Electrons orbit the nucleus

22
Bohrs Model
  • Believed electrons orbited the nucleus in
    specific paths
  • Paths were located on levels and electrons could
    skip levels

23
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24
Nuclear Fission
  • An atom's nucleus can be split apart. When this
    is done, a tremendous amount of energy is
    released.
  • Nuclear power
  • Atomic bomb

25
Nuclear Fusion
  • Fusion means joining smaller nuclei (the plural
    of nucleus) to make a larger nucleus.
  • Example Sun uses nuclear fusion of hydrogen
    atoms into helium atoms.
  • This gives off heat and light and other
    radiation.

26
Fusion by Magnetic Confinement
27
Modern Theory
  • Electrons do not move in Paths
  • The exact path can not be predicted
  • Electron Clouds- regions where electrons are
    found

28
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29
What's inside an Atom
  • Protons
  • Neutrons
  • Electrons

30
Atomic Mass units
  • The SI unit used to express the mass of protons,
    neutron and electrons

31
Nucleus
  • Protons
  • Positively Charged
  • All protons are identical
  • 1 amu
  • Neutrons
  • No Charge
  • 1 amu

32
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33
Electrons
  • Found around the outside of the nucleus in
    electron clouds
  • Have a negative charge
  • 0 amu

34
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35
Atom Charge
  • The amount of neg. and positive charges on an
    atom are equal
  • Atoms have no charge
  • Example -1 1 0

36
Ions
  • Atoms with Charge
  • If more protons, positive
  • If more electrons, negative

37
Isotopes
  • Atoms of the same element with different numbers
    of neutrons
  • For example, the most common isotope of hydrogen
    has no neutrons at all
  • deuterium, with one neutron
  • tritium, with two neutrons

                                                              


Tritium
Hydrogen
Deuterium
38
Properties o Isotopes
  • Limited Isotopes per element
  • Have Unique Properties (unstable)

39
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40
Unstable
  • Meaning the atom nucleus can change it
    composition (radioactive)
  • Most Chemical Physical Properties remain the
    same

41
Differing Isotopes
  • Mass number protons neutrons
  • Remember electrons are not included because there
    amu 0

42
Whats the mass number?
43
12
44
Whats the mass number?
45
39
46
  • http//www.youtube.com/watch?vvDAZsPkTkMM

47
Calculating Atomic Mass
  • Atomic Mass (mass of each Isotope) X
    (Percentage abundance)

48
Steps to Calculating Atomic Mass
  • Given
  • Copper-63 at 69
  • Copper-65 at 31
  • First change percent to decimal form
  • 69 .69
  • 31 .31

49
Percent X Mass Number
  • (63 X .69) 43.47 amu
  • (65 X .31) 20.15 amu

50
Add the Mass
  • 43.47 20.5 63.62 amu

51
Calculating parts of atoms
  • Protons Atomic number
  • Electrons protons

52
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53
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54
Homework
  • Page 89 questions 1-3
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