1. Chap 4 Bell -Ringers

2. The Structure of the Atom
The Atom has a Structure

3. What we’ve seen so far… Chapter 1 The Science of Chemistry
- Chemistry is about discovering and understanding natural laws using the scientific method
- Energy cannot be created nor destroyed
Chapter 1
The Science of Chemistry

4. What we’ve seen so far… Chapter 1 Chapter 2 The Science of Chemistry
- Matter can be mixtures or substances. The smallest unit of a pure substance is an element.
- Each element is a type of atom, and they can be arranged in a periodic table.
- Atoms come together to form compounds. Atoms with an electric charge are known as ions.
Chapter 1
The Science of Chemistry
Chapter 2
Matter and Atoms

5. What we’ve seen so far… Chapter 1 Chapter 2 The Science of Chemistry
Matter and Atoms
Chapter 3
Temperature, Energy, and Heat
- Temperature is a measure of kinetic energy.
- Heat is thermal energy.
- Heat gain and heat loss can cause phase changes, as molecules are rearranged.

6. What we’ve seen so far… Chapter 1 Chapter 2 The Science of Chemistry
Matter and Atoms
Temperature, Energy, and Heat
Physical and Chemical Change
- In a physical change molecules are rearranged. In a chemical change atoms are rearranged to make new substances.
- Chemical reactions can be endothermic or exothermic.
- Many reactions occur in aqueous solution, and some elements are more reactive than others.

7. How can we explain the properties and behaviors observed so far?
Chapter 1
The Science of Chemistry
Chapter 2
Matter and Atoms
Temperature, Energy, and Heat
Physical and Chemical Change
How can we explain the properties and behaviors observed so far?

8. Answers can be found inside the atom
Chapter 1
The Science of Chemistry
Chapter 2
Matter and Atoms
Chapter 3
Temperature, Energy, and Heat
Physical and Chemical Change
How can we explain the properties and behaviors observed so far?

9. 92 different types of atoms!

10. Each of the elements is a unique type of atom.
Atoms are made from smaller particles!
protons
neutrons
electrons
Each of the elements is a unique type of atom.

11. How did scientists come up with this?
Atoms are made from smaller particles!
protons
neutrons
electrons
How did scientists come up with this?

12. It started a long time ago…
460 – 370 BC
Today
Democritus
Beginning of Atomism
You cannot divide something in half forever.
The smallest piece of matter is called an atom.

13. Think of the Rutherford marble tossing lab
How do you find out about something you can’t see?
Think of the conservation of mass labs, distilled wood, even flame test lab
Think of experimentation of the Copper, HCl and Zinc lab
Think of the Rutherford marble tossing lab

14. Bellringer
When scientists wanted to find out what an atom was, they were not able to look directly at what the atom was made of. They had to make inferences from the results of many different experiments. It was like trying to describe a picture, such as the one on the next slide, with only small portions visible.

15. Bellringer, continued
1. Write four sentences describing what you can see of the above picture.
2. What information or parts of the picture would make your descriptions more accurate without revealing the entire picture?

16. Scientists contributing
CHADWICK
THOMSON
RUTHERFORD
DALTON
de BROGLIE
BOHR

17. 1. All elements are made of tiny indivisible particles called atoms.
Dalton’s Postulates
460 – 370 BC
1808
Today
1. All elements are made of tiny indivisible particles called atoms.
Democritus
Atomism
Over 2,000 years later
John Dalton comes up with the first “modern” atomic theory.

18. 1. All elements are made of tiny indivisible particles called atoms.
Dalton’s Postulates
460 – 370 BC
1808
Today
1. All elements are made of tiny indivisible particles called atoms.
Democritus
Atomism
2. All atoms of the same element are the same, but different from atoms of every other element.
Over 2,000 years later
John Dalton comes up with the first “modern” atomic theory.

19. 1. All elements are made of tiny indivisible particles called atoms.
Dalton’s Postulates
460 – 370 BC
1808
Today
1. All elements are made of tiny indivisible particles called atoms.
Democritus
Atomism
2. All atoms of the same element are the same, but different from atoms of every other element.
Over 2,000 years later
John Dalton comes up with the first “modern” atomic theory.
3. Chemical reactions rearrange atoms but do not create, destroy, or convert atoms from one element to another.

20. 1. All elements are made of tiny indivisible particles called atoms.
Dalton’s Postulates
460 – 370 BC
1808
Today
1. All elements are made of tiny indivisible particles called atoms.
Democritus
Atomism
2. All atoms of the same element are the same, but different from atoms of every other element.
Over 2,000 years later
John Dalton comes up with the first “modern” atomic theory.
3. Chemical reactions rearrange atoms but do not create, destroy, or convert atoms from one element to another.
4. Compounds are made from combining atoms in simple whole number ratios.

21. Another kind of light?
460 – 370 BC
1808
1870
Today
Democritus
Atomism
Dalton
“Modern”
atomic theory
William Crookes invents a tube in which virtually all the gas has been removed.
Under high voltage, a ray was emitted from the cathode end of the tube.

22. Cathode rays must be negative.
It started a long time ago…
460 – 370 BC
1808
1870
1897
Today
Democritus
Atomism
Dalton
“Modern”
atomic theory
Crookes
Cathode rays
J.J. Thomson discovers the electron
Cathode rays must be negative.

23. It started a long time ago…
460 – 370 BC
1808
1870
1897
1910
Today
Democritus
Atomism
Dalton
“Modern”
atomic theory
Crookes
Cathode rays
Thomson
Discovery
of the electron
Ernest Rutherford discovers the nucleus

24. Size and mass
The size of the atom comes mostly from the space occupied by the electrons
The mass of the atom comes mostly from the nucleus

25. Charges in the atom
neutrons
protons
electrons

26. Charges in the atom
A complete atom has a charge of zero

27. Charges in the atom

28. What happens when you change the number of protons?
neutrons
protons
electrons
What happens when you change the number of protons?

29. You obtain a different element!
6 protons in carbon
7 protons in nitrogen
8 protons in oxygen
You obtain a different element!
The number of protons is also called the atomic number for that element.

30. The electron cloud Electrons are very light and fast.
They are not organized along orbits around the nucleus.
Except for mass, virtually every property of atoms is determined by electrons, including size and chemical bonding

31. What happens when you change the number of neutrons?
protons
electrons
What happens when you change the number of neutrons?

32. They hold protons together in the nucleus.
Atomic number
Neutrons act as “glue.”
They hold protons together in the nucleus.

33. 12C Mass number = 6 p + 6 n = 12 “carbon-12”
mass number: total number of protons and neutrons in a nucleus.

34. Name
Mass number
# protons
# neutrons

35. Carbon-12 Carbon-13 Carbon-14
Name
Mass number
# protons
# neutrons

36. Carbon-12 Carbon-13 Carbon-14
Name
Mass number
# protons
# neutrons

37. Carbon-12 Carbon-13 Carbon-14
Name
Mass number
# protons
# neutrons

38. Carbon-12 Carbon-13 Carbon-14
Name
Mass number
# protons
# neutrons

39. isotopes: atoms or elements that have the same number of protons in the nucleus but different number of neutrons.

40. How can lithium have 0.941 neutrons?
Two lithium isotopes in nature
Atomic mass
How can lithium have neutrons?

41. Number of neutrons for each of 100 lithium atoms randomly sampled from nature
It’s an AVERAGE mass!

42. Isotope periodic table (first 4 rows)

43. There must be a force that keeps the nucleus together
Forces in the atom
There must be a force that keeps the nucleus together

44. Electrons form bonds between atoms.
Forces in the atom
In the nucleus
Electrons
The strong nuclear force attracts protons to protons, neutrons to neutrons, and protons to protons
Electrons repel each other, but don’t “fall into” the nucleus because they are in constant motion.
Electrons form bonds between atoms.

45. The size of the atom comes mostly from the electrons
460 – 370 BC
1808
1870
1897
1910
Today
Democritus
Atomism
Dalton
“Modern”
atomic theory
Crookes
Cathode rays
Thomson
Discovery
of the electron
Rutherford
Discovery
of the nucleus
electrons
protons
neutrons
The size of the atom comes mostly from the electrons
The mass of the atom comes mostly from the nucleus

46. Who coined the term atom in 4 BC?
Dalton
Democritus
Rutherford
Bohr
Thomson

47. Who stated that elements are made of indivisible spheres called atoms?
Dalton
Chadwick
Rutherford
Bohr
Thomson

48. Who discovered the atom was divisible and had subatomic parts?
Dalton
Chadwick
Rutherford
Bohr
Thomson

49. Who discovered the electron?
Dalton
Chadwick
Rutherford
Bohr
Thomson

50. Who discovered that atoms are mostly empty space?
Dalton
Chadwick
Rutherford
Bohr
Thomson

51. Who discovered the nucleus?
Dalton
Chadwick
Rutherford
Bohr
Thomson

52. Who discovered the proton in the nucleus?
Dalton
Chadwick
Rutherford
Bohr
Thomson

53. Who stated that electrons are located in fixed energy levels?
Dalton
Chadwick
Rutherford
Bohr
Thomson

54. Who discovered the neutron?
Dalton
Chadwick
Rutherford
Bohr
Thomson

55. Center of a atom, contains most of the atom’s mass
Proton
Neutron
Electron
Nucleus
Energy levels
Mass number
Electromagnetic force

56. Positively charged particle that exists in the nucleus of an atom.
Proton
Neutron
Electron
Nucleus
Energy levels
Mass number
Eelctromagnetic force

57. Particle with no charge that exists in the nucleus of an atom
Proton
Neutron
Electron
Nucleus
Energy levels
Mass number
Electromagnetic force

58. The least massive of the three subatomic particles which also carries an negative net charge.
Proton
Neutron
Electron
Nucleus
Energy levels
Mass number
Electromagnetic force

59. Describes how electrons are arranged around an atom
Proton
Neutron
Electron
Nucleus
Energy levels
Mass number
Electromagnetic force

60. The force that holds the positively charged nucleus together is called
Proton
Neutron
Electron
Nucleus
Energy levels
Mass number
Electromagnetic force
Strong nuclear force

61. The force that holds the atom together is called
Proton
Neutron
Electron
Nucleus
Energy levels
Mass number
Electromagnetic force
Strong nuclear force

62. The total number of protons and neutrons in the nucleus of an atom
Electron
Nucleus
Energy levels
Mass number
Electromagnetic force

63. C-12 How many protons? How many electrons? How many neutrons?
Draw a atomic model for this element?
C-12

64. C 14 6 How many protons? How many electrons? How many neutrons?
Draw a atomic model for this element? 14 C 6

65. Li 7 3 How many protons? How many electrons? How many neutrons?
Draw a atomic model for this element? 7 Li 3

66. N 14 How many protons? How many electrons? How many neutrons?
Draw a atomic model for this element? 14 N

67. Na-23 How many protons? How many electrons? How many neutrons?
Draw a atomic model for this element?
Na-23

68. How many protons?
How many neutrons?
238 U

69. Be-9 atomic number? 1 2 3 4 5 6 11

70. Be-9 number of protons? 1 2 3 4 5 6 11

71. Be-9 number of electrons?1 2 3 4 5 6 11

72. Be-9 number of neutrons? 1 2 3 4 5 6 11

73. Be-9 number of energy levels?1 2 3 4 5 6 11

74. 14Si valence electrons? 1 2 3 4 5 6 11

75. 7N valence electrons? 1 2 3 4 5 6 11

76. Be-9 number of electrons in the first energy level?1 2 3 4 5 6 11

77. 17Cl number of electrons in the first energy level?2 3 4 5 6 11

78. Complete the energy levels …7
NITROGEN
# of Protons?
# electrons?
# e’ in 1st orbital?
# e; in 2nd orbital?
# of valence e’ ? 7 2 5 5

79. Who discovered the electron?
Electrons in the outer energy are called?
3. The columns in the periodic table are called
JJ Thomson
Valence electrons
Groups

80. NEED YOUR PERIODIC TABLE
FOR THIS ONE
Find SULFUR (atomic # 16)
How many valence electrons does it have?
Which orbital is being filled? 6
3rd

81. Element or compound?? Hydrochloric acid HCl
2. What element is most closely related to Bromine?
3. What does the group # tell us?
Compound
Fluorine / Chlorine
The # of valence electrons

82. # of the energy level being filled
1. Who did the gold-foil experiment?
2. Who stated that elements are made of atoms?
3. What does the period # tell us?
4. Who created the term “atomos”?
Rutherford
Dalton
# of the energy level being filled
Democritus

83. Which are the metals?
Nonmetals? B A B C A