1. Matter & The Atom

2. Matter Anything that takes up space and has mass
Can be classified as solid, liquid, gas or plasma

3. Is it matter?

4. What is not matter? Properties of Matter
ENERGY, HEAT, LIGHT, ELECTROMAGNETIC WAVES, MAGNETIC FIELDS, IDEAS, ETC.
Properties of Matter
Describe the characteristics and behavior of matter, including the changes that matter undergoes

5. Observing Matter
Macroscopic Observations: Observations made with the 5 senses
Microscopic Observations: Observations made with a microscope
Submicroscopic Observations: Observations of substances so small they cannot even be seen with a microscope
Macroscopic
Microscopic
Submicroscopic

6. Qualitative Observation: Describes the properties of a substance
Quantitative Observation: An observation that involves a numerical value.

7. What are the physical properties represented in the image above?
quantitative
characteristics
qualitative
What are the physical properties represented in the image above?

8. Chemical Properties

9. MIXTURES Two or more elements physically combined.
How can you tell something is a mixture?
It can be physically separated into its parts.

10. Heterogeneous Mixtures
The prefix “hetero” means “different”
A mixture with different compositions throughout
You can see each phase (part) of the mixture

11. Homogeneous Mixtures The prefix “homo-” means “the same”
A mixture that is the same throughout
You cannot see the phases (parts) of the mixture.

12. HETEROGENEOUS OR HOMOGENEOUS?

13. Solutions Solute: The substance being dissolved in a solution
Solvent: The substance that dissolves the solute
Aqueous Solution: A solution in which water is the solvent

14. What is the solute? What is the solvent?
82% Fe
18% Cr

15. ALLOY NAME OF ALLOY % MAKE UP EXAMPLE Stainless Steel 73-79% Fe
14-18% Cr
7-9% Ni
Sterling Silver
92.5% Ag
7.5% Cu
18-karat white gold
75% Au
12.5% Ag
12.5% Cu
14 karat gold
58% Au
14-28% Ag
14-28% Cu

16. Methods to Separate Mixtures
Filtration: Separates a solid from a liquid

17. Separating…
Magnet: Separates Fe, Co, or Ni

18. Separating…
Distillation: Separates two or more liquids with different boiling points.

19. Separating…
Crystallization: Separates crystalline solids from a saturated liquid

20. Separating…
Chromatography: Separates different types of liquids

21. PURE SUBSTANCE Matter with the same fixed composition and properties
First Type of Pure Substance
Element
The Periodic Table: A chart that lists the chemical name and chemical symbol for each element
Chemical Symbol: A shorthand abbreviation for the name of an element
You can tell a substance is an element because it is on the periodic table
-Can you separate an element? No
Aluminum = ___ Gold = ____ Tin = ____

22. PURE SUBSTANCE Matter with the same fixed composition and properties
Second Type of Pure Substance
Compound
Chemical Formula: A combination of chemical symbols that show what elements make up a compound and the number of atoms of each element
Subscript: A number written to the lower right of an element symbol to indicate the number of atoms of that
How do you know if a substance is a compound? If it is 1 thing only—and it is not on the periodic table.
Can you separate a compound? Yes—by chemically decomposing it.
NaH2CO3 Mg(OH)2

23. Decomposing a Compound
Electrolysis
“To tear apart with electricity”
The process in which electrical energy causes a non-spontaneous chemical reaction to occur
May break a compound apart into its elements
Electrolysis of PbBr2 & ZnCl2
Electrolysis of Water

24. THE GREEK PHILOSOPHERS
250 B.C.
Four Fundamental Elements: Earth, Wind, Water, and Fire made up everything in the world

25. DEMOCRITUS
450 B.C.
Seashell experiment led to development of the idea of an indivisible piece of matter called “atomos”
Atom: The building block of matter
Problem: No experimental data to back his concept
Aristotle: Discredited Democritus

26. DEMOCRITUS’ ATOM

27. Law of Conservation of Mass
Antoine Lavoisier (Mercury & Oxygen Experiment)
Mass cannot be created nor destroyed in a chemical reaction
The mass of the reactants must equal the mass of the products in a chemical reaction

28. Law of Definite Proportions
Joseph Louis Proust-1799
In a pure compound, the elements combine in definite proportions to one another according to mass
Water is always 2 Hydrogen : 1 Oxygen

29. Law of Definite Proportions
Malachite

30. John Dalton-1803 Elements are made of tiny particles called atoms
All atoms of a given element are identical
Atoms of a given element are different then every other element
Atoms of one element can combine with atoms of another element to form compounds
Atoms are indivisible and indestructible. Atoms can only be rearranged in chemical reactions--not created, divided, nor destroyed.

31. DALTON’S ATOM

32. Benjamin Franklin-1700’s Kite experiment:
Objects have 1 of 2 electric charges
Called them + & -
Like charges repel
Opposite charges attract

33. Michael Faraday--1839
Suggested that atoms contain particles that have electrical charge
Electricity (elektron, Greek word for amber)
The flow of electrons in a substance
Static: Stationary
Static Electricity: Electrical charges not in motion (socks out of a dryer)

34. J.J. THOMSON--1897
CATHODE RAY TUBE: Evacuated glass tube in which a stream of electrons emitted by a cathode strikes a fluorescent material, causing it to glow
CATHODE: The electrode that brings electrons to the ions or atoms in a solution.

35. TELEVISIONS ARE CATHODE RAY TUBES

36. THOMSON’S PLUM-PUDDING MODEL OF THE ATOM
Thomson measured the degree to which a magnetic field and an electric field deflected the cathode ray. Since the field was attracted to the positive charge, he knew it must contain a negative charge. By doing this he discovered the electron.
Electron’s (negatively charged particles) are embedded in a ball of positive charge.

37. Henri Becquerel--1896
Accidentally placed uranium on unexposed photographic film
Found an image had been produced on the film
Discovered that uranium exhibits radioactivity

38. Radioactivity
Radioactivity is the spontaneous emission of radiation from an element
Marie & Pierre Curie were awarded the Noble Peace Prize, along with Becquerel, for the discovery of radioactivity
The Curies isolated two other radioactive elements—radium and polonium
Elements with atomic numbers greater than 83 are radioactive

39. Robert Millikan—1909 Oil Drop Experiment
Using this experiment, Millikan determined the charge of the electron

40. Ernest Rutherford Alpha particle (α)—a particle with a +2 charge
Beta particles ()—high-speed electrons
Gamma radiation ()—not composed of particles

41. RUTHERFORD’S GOLD FOIL EXPERIMENT--1911
If Thomson’s model was correct, positive α particles would all go straight through the atom. However, Rutherford’s Gold Foil Experiment proved this to be untrue. Instead, every once in a while the α particle was repelled. Since α particles are positive, that meant there was a small, positive part of the atom.

42. RUTHERFORD’S NUCLEAR MODEL OF THE ATOM
-- Center of the atom
-- subatomic particle with no charge located in the nucleus
-- subatomic particle with a positive charge located in the nucleus
Concept: The atom is made of mostly empty space, containing electrons, surrounding a small, dense, positively charged nucleus.

43. James Chadwick—1930’s

44. Scanning Tunneling Microscope (STM)

45. STM IMAGES
Nickel
Platinum
Iron on Copper

46. WHO RECEIVED THE NOBEL PRIZE FOR STM IN 1986?
Gerd Binnig and Heinrich Rohrer of the IBM Research Laboratory
1981-Invented the STM which formed images of individual atoms

47. Carbon Monoxide Man (on Platinum)
ATOM MANIPULATION
Xenon on Nickel
Iron on Copper
Carbon Monoxide Man (on Platinum)

48. Particle Accelerator--FermiLab

49. What’s smaller than a proton?
Atoms are composed of protons, electrons & neutrons which explain the behavior of matter.
Other particles: quarks, gluons, mesons, muons & other exotic particles—no immediate chemical impact

50. A typical atom is 0.000000001 meter across or 1 billionth of a meter
ATOMIC SIZE
A typical atom is meter across or 1 billionth of a meter
A quark is meter

51. ATOMIC SIZE
If the atom was the same size as the distance between the Earth and the Moon then:
-the nucleus would be the length of a golf course
-a proton would be about the size of a football field
-a quark would be about the size of a golf ball

52. Amu = atomic mass units= 1/12 the mass of a carbon-12 atom
SUBATOMIC PARTICLES
Symbol
Charge (relative)
Location
Mass (relative)
Electron e- -1
Outside nucleus
0 amu
Proton p+ +1
Inside nucleus
1 amu
Neutron n0
Amu = atomic mass units= 1/12 the mass of a carbon-12 atom

53. Atomic Number = # of protons In an ATOM also = # of _________________
because: an ATOM is electrically neutral
so: the positive = the negative

54. A lithium atom with 3 protons & 3 electrons has no overall charge.
(+3) + (-3) = 0
A boron atom with 5 protons & 5 electrons has no overall charge.
5 protons + 5 electrons =
(+5) + (-5) = 0
protons
electrons

55. Atomic Number
The atomic number is the number that is always used to identify an element
Each element has a unique # of protons and the number of protons of a particular element can never change
The elements are arranged by atomic number on the periodic table

56. Example 10 Ag 62 Element Name Element Symbol Atomic Number
# of protons
# of electrons 10 Ag 62

57. ISOTOPES
Isotopes: Different atoms of the same element with the same number of protons but a different number of neutrons
What’s this mean? There are different types of the same element
Isotopes of the same element are: chemically alike, because they have the same number of protons & electrons
90% of the universe, H2O
D2O (moderator in nuclear reactors to slow down neutrons)
Radioactive, produced in nuclear reactors, fission bombs

58. Carbon Isotopes

59. Mass # must be calculated, it cannot be found on the periodic table!
MASS NUMBER
Mass Number: The sum of the isotope’s number of protons and neutrons
-The mass number is the mass of just 1 of the element’s isotopes
-The mass number is always a whole number
Mass Number = (# of p+) + (# of no)
Neutrons =
Mass # must be calculated, it cannot be found on the periodic table!

60. A P E M A N TOMIC NUMBER ASS NUMBER TOMIC NUMBER ROTONS LECTRONS
EUTRONS =
& = +

61. Examples What is the mass number of an atom with 17
protons and 20 neutrons?
How many neutrons does a carbon atom with
a mass number of 14 have?

62. ISOTOPES Symbol Isotopic Symbol: Mass # Naming an Isotope:
Atomic #
Naming an Isotope:
Element Name-Mass #
Symbol

63. EXAMPLES
Write the isotopic symbols for the element with:
21 protons, 24 neutrons
53 protons, 74 neutrons
How many protons, electrons and neutrons are in an atom of 3215P?

64. EXAMPLE OF AN ISOTOPE Isotope Isotopic Symbol Mass # Atomic #
# of Protons
# of Neutrons
Carbon-12
Carbon-13

65. ISOTOPES Atomic Mass Unit: Unit for atomic mass
1 amu = 1/12 (mass of carbon-12 atom)
= 1.66 x g
Atomic Mass: a weighted average of all of the isotopes of an element
Different from mass number
Is found on the periodic table
the atomic mass value will be closest to the mass of the isotope that is most abundant

66. ATOMIC MASS To calculate atomic mass:
Atomic Mass = [(% abundance isotope 1) x (mass of isotope 1)] + [(% abundance isotope 2) x (mass of isotope 2) ] + …
Example: Calculate the atomic mass of carbon if carbon-12 has a percent
abundance of 98.89% and carbon-13 has a percent abundance of 1.11%.