1. CHEMISTRY!!!!

2. Subatomic particles Relative mass Actual mass (g) Name Symbol Charge
Electron e- -1
1/1840
9.11 x 10-28
Proton p+ +1 1
1.67 x 10-24
Neutron n0 1
1.67 x 10-24

3. Counting the Pieces Atomic Number = number of protons in the nucleus
# of protons determines kind of atom (since all protons are alike!)
the same as the number of electrons in the neutral atom.
Mass Number = the number of protons + neutrons.
These account for most of mass

4. Counting the Pieces Protons: equal to atomic number
Neutrons: Mass Number – Atomic Number
Electrons: In a neutral atom equal to atomic number

5. Symbols
Contain the symbol of the element, the mass number and the atomic number.

6. Symbols
Contain the symbol of the element, the mass number and the atomic number.
Mass
number X
Atomic
number

7. F Symbols 19 9 Find the number of protons number of neutrons
number of electrons
Atomic number
Mass Number 19 F 9

8. Br Symbols 80 35 Find the number of protons number of neutrons
number of electrons
Atomic number
Mass Number 80 Br 35

9. Symbols
if an element has an atomic number of 34 and a mass number of 78 what is the
number of protons
number of neutrons
number of electrons
Complete symbol

10. Symbols if an element has 91 protons and 140 neutrons what is the
Atomic number
Mass number
number of electrons
Complete symbol

11. Symbols if an element has 78 electrons and 117 neutrons what is the
Atomic number
Mass number
Number of protons
Complete symbol

12. What if Atoms Aren’t Neutral
Ions: charged atoms resulting from the loss or gain of electrons

13. What if Atoms Aren’t Neutral
Anion: negatively charged ion; result from gaining electrons
Take the number of electrons in a neutral atom and add the absolute value of the charge
Identify:
Number of Protons
Number of Neutrons
Number of Electrons 81 1- Br 35

14. What if Atoms Aren’t Neutral
Cation: positively charged ion; result from the loss of electrons
Take the number of electrons in a neutral atom and subtract the value of the charge
Identify:
Number of Protons
Number of Neutrons
Number of Electrons 27 Al 3+ 13

15. Isotopes
Atoms of the same element can have different numbers of neutrons
Different mass numbers
Called isotopes

16. Naming Isotopes
We can also put the mass number after the name of the element.
carbon- 12
carbon -14
uranium-235

17. Atomic Mass How heavy is an atom of oxygen?
There are different kinds of oxygen atoms
We are more concerned with average atomic mass
Average atomic mass is based on abundance of each element in nature.
We don’t use grams because the numbers would be too small

18. Measuring Atomic Mass Unit is the Atomic Mass Unit (amu)
It is one twelfth the mass of a carbon- 12 atom
Each isotope has its own atomic mass, thus we determine the average from percent abundance

20. Pure Substances Cannot be physically separated
Every sample has the same characteristics and they can be used to identify a substance

21. Elements Are made up of ONE type of atom
Atoms are the smallest unit of an element that maintains the chemical identity of that element
They can be found on the Periodic Table
Examples: Carbon, Nitrogen, Calcium

22. Compounds Can be broken down into simple stable substances
Are made up of two or more types of atoms that are chemically bonded
Examples: Water (H2O), sugar (C12H22O11)

23. Mixtures
A blend of two or more kinds of matter, each which retains its own identity and properties

24. Homogeneous Mixtures Have uniform composition Also known as SOLUTIONS
Examples: salt water, tea

25. Solutions ALLOYS are solid solutions that contain at least 1 metal
They are blended together so that they have more desirable properties
Some alloys you may know are:
Stainless Steel: iron, chromium, and zinc
Brass: zinc and copper
Bronze: tin and copper
Sterling Silver: copper and silver

26. Heterogeneous Mixtures
Do not have uniform composition
You can see the particles in them
Examples:
Sand on the beach (contains sand, shells, rocks, bugs, etc)
Soil (contains dirt, rocks, worms, etc)
Chicken Soup (contains water, chicken, veggies etc)

27. Suspensions
A heterogeneous mixture where the solid particles eventually settle out of solution
Examples:
Muddy water
Mixtures of two solids
Paint

28. Properties of Matter
All pure substances have characteristic properties
Properties are used to distinguish between substances
Properties are also used to separate substances

29. Physical Properties
A Physical Property is a characteristic that can be observed or measured without changing the composition of the substance
Physical properties describe the substance itself
Examples
Physical State
Color
Mass, shape, length
Magnetic properties

30. Chemical Properties
A Chemical Property indicates how a substance will react with another
Chemical properties cannot be determined without changing the identity of the substance
Examples:
Iron Rusting
Silver Tarnishing

31. Physical Changes
A Physical Change is a change in a substance that does not alter the substance’s identity
Examples:
Grinding
Cutting
Melting
Boiling

32. Chemical Changes
A change in which one or more substances are converted into different substances is called a Chemical Change
Signs of a Chemical Change:
Color Change
Gas is Released
Temperature Change
Precipitate – Solid falls out of solution
Substance Disappears

33. How Atoms Combine
Two or more atoms that are chemically combined make up a compound
The combination results in a chemical bond, a force which holds elements together in a compound

34. Covalent Bonds
Covalent Bonds are formed when atoms in a compound share electrons
Molecule – two or more atoms held together by a covalent bond
Usually occurs between nonmetals

35. Covalent Bonding in Water

36. Ions An atom that has gained or lost an electron is called an ion.
Multiple atoms can combine to form an ion – called a Polyatomic Ion
Silicate (SiO44-) and Carbonate (CO32-) are important in forming materials at Earth’s Surface

37. Ionic Bonding Positive and negative ions attract each other
Ionic Bonds occur when oppositely charged ions form a compound
Usually consist of 1 metal and 1 nonmetal
Positive ion written first in chemical formula (NaCl)
Ionic compounds have a neutral charge

38. Ionic Bonding in NaCl

39. Metallic Bonds Metals share valence electrons between all atoms
Like a group of positive ions in a sea of electrons

40. Atomic Theory and Structure

41. Democritus Democritus added:
Matter is composed of atoms which move through empty space
Atoms are solid, homogeneous, indestructible, and indivisible
Different atoms have different shapes and sizes
The size, shape, and movement of atoms determine their properties

42. Leading to the modern theory
Late 1700’s - John Dalton- England.
Teacher- summarized results of his experiments and those of others.
Dalton’s Atomic Theory
Combined ideas of elements with that of atoms.
Saw atoms as small solid spheres. Billiard Ball Model.

43. Dalton’s Atomic Theory
All matter is made of tiny indivisible particles called atoms.
Atoms of the same element are identical, those of atoms of different elements are different.
Atoms of different elements combine in whole number ratios to form compounds.
Chemical reactions involve the rearrangement of atoms. No new atoms are created or destroyed.

44. Law of Conservation of Mass
The law of conservation of mass states that matter is neither created nor destroyed in chemical reactions

45. Discovery of the Electron
J. J. Thomson - English physicist. 1897
Made a piece of equipment called a cathode ray tube.
It is a vacuum tube - all the air has been pumped out.

46. Thomson’s Experiment
Voltage source - +
Vacuum tube
Metal Disks

47. Thomson’s Experiment
Voltage source - +

48. Thomson’s Experiment
Voltage source - +

49. Thomson’s Experiment
Voltage source - +

50. - + Thomson’s Experiment
Voltage source - +
Passing an electric current makes a beam appear to move from the negative to the positive end

51. - + Thomson’s Experiment
Voltage source - +
Passing an electric current makes a beam appear to move from the negative to the positive end

52. - + Thomson’s Experiment
Voltage source - +
Passing an electric current makes a beam appear to move from the negative to the positive end

53. - + Thomson’s Experiment
Voltage source - +
Passing an electric current makes a beam appear to move from the negative to the positive end

54. Thomson’s Experiment
Voltage source
By adding an electric field

55. Thomson’s Experiment
Voltage source + -
By adding an electric field

56. Thomson’s Experiment
Voltage source + -
By adding an electric field

57. Thomson’s Experiment
Voltage source + -
By adding an electric field

58. Thomson’s Experiment
Voltage source + -
By adding an electric field

59. Thomson’s Experiment
Voltage source + -
By adding an electric field

60. Thomson’s Experiment
Voltage source + -
By adding an electric field he found that the moving pieces were negative

61. Plum Pudding Model Proposed by JJ Thomson
Said the atom had a uniform positive charge in which the negatively charged electrons resided

62. Fluorescent
Screen
Lead block
Uranium
Gold Foil

63. He Expected
The alpha particles to pass through without changing direction very much.
Because…?
…the positive charges were thought to be spread out evenly. Alone they were not enough to stop the alpha particles.

64. What he expected

65. Because

66. He thought the mass was evenly distributed in the atom

67. Since he thought the mass was evenly distributed in the atom

68. What he got

69. How he explained it + Atom is mostly empty.
Small dense, positive piece
at center.
Alpha particles are deflected by it if they get close enough. +

70. +

71. The Bohr Ring Atom
n = 4
n = 3
n = 2
n = 1

72. Electron Cloud Theory

73. What are acids and bases?
ACIDS BASES
TASTE SOUR BITTER
FEEL STINGS SLIPPERY
REACTIONS YES / METAL NO / METALS
CONDUCTS ELECTROLYTE ELECTROLYTE
RELEASES H OH-

74. HOW DO WE MEASURE ACIDS AND BASES?
INDICATORS
A SUBSTANCE THAT TURNS ONE COLOR IN AN ACIDIC SOLUTION AND ANOTHER COLOR IN A BASIC SOLUTION
SOME INDICATORS ARE:
LITMUS: DYE THAT COMES FROM A LICHEN
PHENOLPHTHALEIN: INDICATES ONLY BASES
UNIVERSAL INDICATOR:
ACID, NEUTRALS, BASES
CABBAGE JUICE:
ACIDS, NEUTRAL, BASE