1. The Atom
Chapter 14

2. What would happen if…..
you cut a rock in half ?

3. What would happen if…..
you cut the rock in half again ?

4. What would happen if…..
you cut it in half again ?

5. ..and if you cut it again?

6. ..and if you cut it again?

7. ..and again?

8. Can you keep going?

9. If you could keep going and going you would reach the very smallest particle of matter

10. ……an atom the fundamental building block of all matter

11. If you could fill the earth with ping-pong balls…
So how small is an atom?
If you could fill the earth with ping-pong balls…

12. That’s how many atoms are in a baseball!

13. How many atoms are in an apple?

14. The same amount of apples that could fill the earth!

15. We can’t see them with a microscope
atom

16. They are smaller than visible light waves
atom

17. An object must be larger than visible light waves to be seen

18. Where do atoms come from?
YouTube - The Big Bang

19. Hydrogen - The First Atom
The smallest atom
Makes up more than 90% of all atoms in the universe!

20. Question
Are the atoms in a baby’s body younger than the atoms in the mother?

21. Answer No
Everything on earth is made of atoms that were created billions of years ago!

22. We are all made of stardust!

23. A Breath of Air How many atoms of air are in your lungs?
1 x atoms/liter of air

24. 1 x atoms/liter of air
About the same number of breaths of air in Earth’s atmosphere 1 x liters

25. Think about this…..

26. Several years from now,
this breath will be mixed evenly around the world!

27. Every person will take in 1 atom from that breath with every inhalation!

28. Question
How many zeros are in the number 1022 when not written in exponential form?
Answer 22
10,000,000,000,000,000,000,000
Wow! That’s huge!

29. 1022 Golf Balls
Would fill the North and South Atlantic Oceans!

30. 5,000,000,000,000,000,000,000 F.Y.I. Question F.Y.I. Answer 5 x 1021
If you had half as many atoms as 1022, (10,000,000,000,000,000,000,000) how many atoms would you have?
F.Y.I. Answer
5,000,000,000,000,000,000,000
5 x 1021
Be careful! It’s not 1011!

31. Evidence for Atoms
Chapter 14.2

32. Atoms are so small…….
Not even 40 microscopes stacked on top of each other can see them!

33. Early 1800’s
Scientists first hypothesized about the existence of atoms
It explained why some substances change or transform

34. Explained changes like rusting
Iron atoms + Oxygen atoms Rust

35. Thinking about atoms lead to new discoveries

36. New Medicines

37. Man Made Dyes

38. First direct evidence of atoms 1887
Robert Brown
Scottish botanist
First direct evidence of atoms

39. Studying pollen grains under a microscope

40. Soot and dust also moved.
The pollen was moving!
Soot and dust also moved.

41. Brownian Motion

42. Noted Brownian motion due to atoms colliding with objects.
Albert Einstein
Noted Brownian motion due to atoms colliding with objects.

43. Question Why are atoms invisible?
Answer
They are smaller than visible light waves and therefore can not reflect light

44. Scanning probe microscope

45. We’ve come a long way since Robert Browning!
Scanning probe microscope
Each dot is a few thousand gold atoms
Gallium and arsenic atoms
We’ve come a long way since Robert Browning!

46. The Atom Consists of a: NUCLEUS = protons and neutrons
ELECTRONS = occupy space outside of the nucleus

47. Atomic Composition

48. Hydrogen – the smallest atom
1 electron
1 proton

49. Take a Look at Helium

50. How many different kinds of atoms are there?
Element Song

51. These atoms combine to form all the different substances known to man!

52. consist of only 1 kind of atom
Elements
consist of only 1 kind of atom

53. The Elemental you
YOU are 99% C, H, O and N

54. A First Look at the Periodic Table

55. All the elements are listed on the Periodic Table

56. All the elements are listed on the Periodic Table

57. Symbols of Elements Use 1 or 2 letter abbreviations
Capitalize the first letter only
Examples
C Carbon Co Cobalt
N Nitrogen Ca Calcium
F Fluorine Br Bromine
O Oxygen Mg Magnesium

58. Symbols from Latin Names

59. The Periodic Table How many elements are there?
Tom Lehrer's "The Elements". A Flash animation by Mike Stanfill, Private Hand
How many elements are there?

60. The Periodic Table
Dimitri Mendeleev

62. Check up…
How can you tell that the element potassium, K, was identified by humans before the element Nickel, Ni?
Answer
The atomic symbol for potassium does not match its modern name. It comes from its Latin name.

63. Another check up… Answer
Which is larger, a potassium atom , K, or a nickel atom, N?
Answer
A potassium atom, K, is larger than a nickel atom, Ni.

64. Last one…..
Which is more massive, a potassium atom, K, or a nickel atom, Ni?
Answer
A nickel atom, Ni, is more massive than a potassium atom, K.

65. Protons and Neutrons
Chapter 14.3

66. Now we know that atoms are not the smallest particles of matter!

67. Let’s Review the Atom Consists of a: NUCLEUS = protons and neutrons
ELECTRONS = occupy space outside of the nucleus
Cloud of negative electrons

68. Protons Positive electrical charge
Mass is nearly 2000 X the mass of an electron
The # of protons in the nucleus = the # of electrons

69. How do the atoms of one element differ from those of another element?

70. Each element is identified by its atomic number7 6 79
The # of protons in the nucleus

71. How many protons are in an iron , Fe, atom?

72. Neutrons No electrical charge - neutral
Mass is also nearly 2000 X the mass of an electron
Slightly more mass than a proton

75. Hydrogen vs. Helium Atomic mass 1 amu Atomic mass 4 amu e e P N N P P

76. Now look at the periodic table1
1.007 He 2
4.003
The atomic mass includes the mass of an atom’s protons and neutrons

77. Do you remember? Where are nucleons found? Answer
In the atom’s nucleus

78. Isotopes and Atomic Mass
Chapter 14.4

79. The atoms of each element have a constant # of protons79 7 6

80. However……sometimes the # of neutrons varies
Isotopes

81. What is the mass number of each isotope?
1 amu 2 amu 3 amu amu 55 amu

82. Another way to represent an isotope
mass number
-atomic number
number of neutrons

83. How many neutrons are in the isotope lithium -7?
mass number
-atomic number
number of neutrons 4

84. Each of the elements C, O, N, & H has 2 or 3 naturally occurring isotopes.

85. 12C and 14C
14C is radioactive
Used in radioactive dating

86. We work with the average atomic mass of an element.

87. Atomic number vs Atomic MassH 1
1.007 He 2
4.003
Atomic Number
Atomic Mass
The atomic mass includes the mass of an atom’s protons and neutrons

88. Atomic number vs Mass number
The atomic mass includes the mass of an atom’s protons and neutrons

89. Terms you should know Nucleon Atomic mass Mass number Atomic number
Proton
Neutron
Electron
Isotope