1. STAAR Reporting Category 1 Matter & Energy

2. Atoms and Elements

3. The Structure of an Atom nucleus + + + + + + Proton (+) neutron (o) electron cloud electron (-)

4. Location and Mass of Atomic Particles Inside the Nucleus Protons with a POSITIVE charge AND Neutrons with a NEUTRAL charge (no charge) Both have about the same mass Outside the Nucleus Electrons with a NEGATIVE charge VERY, VERY tiny and do not contribute to the mass of the atom It takes 2000 electrons to equal the mass of one proton or neutron

6. Elements are listed on the Periodic Table

7. Atomic Number Number of PROTONS and determine which element the atom is

8. Atomic Mass the number of PROTONS + NEUTRONS First, round the atomic mass to the nearest whole number Round to 28 How do I calculate # of NEUTRONS???

9. Then, subtract the Atomic number (# protons) from the Atomic mass (total # protons and neutrons 28 (Atomic mass) -14 ( Atomic number ) 14 NEUTRONS

10. Is there an EASIER way to remember all of this? All you have to do is remember: A=P=E M-A=N

11. A=P=E Atomic Number = Protons = Electrons If I know ONE, I know them ALL!!

12. M-A=N Mass - Atomic Number = Neutrons

13. SymbolAtomic # Mass # Protons # Neutrons # Electrons He242 3733 N777 PRACTICE TIME Use your Periodic Table!! Li 22 4 7 14

14. Electrons and Bohr Diagrams 1)Find your element on the periodic table. 2)Determine the number of electrons – remember, it is the same as the atomic number. 3)This is how many electrons you will draw.

15. Bohr Diagrams 6 P 6 N 6 P 6 N Draw a nucleus with the number of protons and neutrons inside.

16. Bohr Diagrams 1)Add the electrons. 2)Carbon has 6 electrons. 3)The first shell can only hold 2 electrons. Always start in the first shell 6 P 6 N 6 P 6 N

17. Bohr Diagrams 1)Since you have 2 electrons already drawn, you need to add 4 more. 2)These go in the 2 nd shell. 6 P 6 N 6 P 6 N

18. Bohr Diagrams 1)Check your work. 2)You should have 6 total electrons for Carbon. 3)Only two electrons can fit in the 1 st shell. 4)The 2 nd and 3 rd shells can hold up to 8 electrons. 6 P 6 N 6 P 6 N

19. Bohr Diagrams Try the following elements on your own: a)H b)He c)O d)Al e)Ne f)K

20. Bohr Diagrams Try the following elements on your own: a)H – 1 electron b)He c)O d)Al e)Ne f)Na 1 P

21. Bohr Diagrams Try the following elements on your own: a)H b)He - 2 electrons c)O d)Al e)Ne f)Na 2 P 2 N 2 P 2 N

22. Bohr Diagrams Try the following elements on your own: a)H b)He c)O - 8 electrons d)Al e)Ne f)Na 8 P 8 N 8 P 8 N

23. Bohr Diagrams Try the following elements on your own: a)H b)He c)O d)Al - 13 electrons e)Ne f)Na 13 P 14 N 13 P 14 N

24. Bohr Diagrams Try the following elements on your own: a)H b)He c)O d)Al e)Ne - 10 electrons f)Na 10 P 10 N 10 P 10 N

25. Bohr Diagrams Try the following elements on your own: a)H b)He c)O d)Al e)Ne f)Na - 11 electrons 11 P 12 N 11 P 12 N

26. Valence Electrons Found on the outermost energy level –Determine how an element will react chemically

27. Lewis Structures How many valence electrons does nitrogen have? 5

28. Learning Check How many valence electrons in each atom? Heliu m Oxygen Sodium 2 6 1

29. Charges of Atoms Most atoms have a NEUTRAL CHARGE since they have equal numbers of protons (+) and electrons (-). Some atoms gain or lose electrons to become IONS. IONS are not neutral and the atom becomes positively or negatively charged. Let’s see how this works...

30. +++++ in an atom, protons ( ) are in the center and electrons ( ) are on the outside +

31. +++++ only electrons ( ) can be added or taken away

32. +++++ this is an atom with 5 electrons and 5 protons

33. +++++ the atom is neutral net charge = zero 5 (-) and 5 (+) = zero charge (neutral)

34. +++++ 6 (-) and 5 (+) = -1 charge = ?

35. +++++ 3 (-) and 5 (+) = +2 charge = ?

36. WHEN REMOVING ELECTRONS THE RESULTING CHARGE IS POSITIVE neutral +1

37. THE RESULTING CHARGE IS NEGATIVE neutral -2 WHEN ADDING ELECTRONS

38. Elements are substances: that cannot be broken down into other substances that are made of atoms with the same number of protons in the nucleus

39. Elements are ORGANIZED on the Periodic Table

40. Elements with similar properties are placed in the same group in the periodic table. The stair-step line separates the elements into metals and nonmetals.

41. Groups of Elements Alkali Metals Group 1, highly reactive, 1 valence electron Soft metals with low melting points

42. Alkaline Earth Metals Group 2, reactive, 2 valence electrons Hard metals with high melting points

43. Transition Metals Group 3-12, variable # of valence electrons Unpredictable, don’t follow “reactivity” rules

44. Halogens Group 17, highly reactive, 7 valence electrons Form “salts”

45. Noble Gases Group 18, full outer shells (2 in He and 8 in others) NON-REACTIVE

46. Rare Earth Elements Group 3, Period 6 and 7 Special group of transition metals Many are synthetic and/or radioactive

47. Metalloids Non-metal elements that are conductors of heat and electricity

48. Periodic Trends Elements are arranged into horizontal rows called PERIODS Elements within a period have the same number of ENERGY LEVELS 1 energy level 2 energy levels 3 energy levels 7 energy levels 6 energy levels 5 energy levels 4 energy levels

49. Elements are arranged in vertical columns called GROUPS –have same number of VALENCE ELECTRONS –share similar CHEMICAL properties 4 valence electrons 6 valence electrons 2 valence electrons 1 valence electron 3 valence electrons 5 valence electrons 7 valence electrons 8 valence electrons

50. Metal Properties Shiny solids Ductile (able to be stretched) Malleable (able to be shaped) Good conductors of heat and electricity Magnetic

51. Nonmetal Properties May be solids, liquids or gases Dull, brittle solids Poor conductors of heat and electricity Non-magnetic

52. Metalloid Properties Nonmetals with properties of both metals and non-metals Weak conductors of heat and electricity

53. Atomic Theory Atoms are building blocks of elements Atoms in each unique element are the same. (Ex: Every oxygen element has the same # of protons) Atoms are different from atoms of other elements (Ex: Hydrogen has a different # of protons than oxygen) Two or more different atoms bond in simple ratios to form compounds (Ex: Hydrogen & oxygen can chemically combine to form water- H 2 O )

54. Writing Chemical Symbols 1. First letter is capitalized 2. Second letter is lower case 3. NO period at the end H Cl O Hg Fe Sn C He

55. Co or CO Does it really matter?

56. Alloys for metals used in jet turbines Co = cobalt

57. carbon monoxide  Colorless  Odorless  Poisonous gas carbon oxygen CO Compound

59. Compounds 2 or More Elements Chemically Combined Oxygen Hydrogen 2-H: 1-O

60. Water H H O Ratio 2:1 Formulas use element symbols with subscript numbers H2OH2O 1 is not shown

61. Change the ratio Change the substance 2:2 H2O2H2O2 Subscript numbers http://www.wonderquest.com/images/2003-08-08-peroxide.jpg Hydrogen Peroxide

62. No subscripts?? NaCl 1Na 1Cl How many elements? Salt 2

63. Chemical Changes A chemical change is a change in which both the physical and chemical properties of the original substance are changed. The new substance has new physical and chemical properties. Burning is a chemical change.

64. A chemical change is the result of a Chemical Reaction. A chemical reaction occurs when atoms separate, come together, or rearrange to form new substances with new properties.

65. Example of a Chemical Reaction Reactant + Reactant  Product (goes to) carbon + oxygen  carbon dioxide (has different properties)

66. C + O 2  CO 2 Is the product the same as the reactants? No, the atoms have been rearranged.

67. For Example… A chemical reaction takes place during photosynthesis. 6CO 2 + 6H 2 O  C 6 H 12 O 6 + 6O 2 Carbon dioxide reacts with water to form glucose (a sugar) and oxygen.

68. copper + oxygen  copper oxide 2 Cu O 2 2 CuO Cu O CuO balanced 2 copper atoms 2 oxygen atoms in a molecule (O 2 )

69. 2 copper atoms 2 copper atoms =balanced= 2 oxygen atoms 2 oxygen atoms Since nothing is lost or gained, there is no loss or gain in mass (atoms). You can say the equation is balanced.

70. The Law of conservation of mass states that matter cannot be created or destroyed in any chemical reaction The atoms in the reactants are rearranged to form new compounds, but none of the atoms disappear, and no new atoms are formed. H H H H O O Reactants Products

71. Remember that atoms don’t change in a chemical reaction. The number and kinds of atoms present in the reactants of a chemical reaction are the same as those present in the products. When stated this way, it becomes the law of conservation of atoms.

72. So: Chemical equations are balanced, when the numbers and kinds of atoms on each side of the reaction arrow are equal. H H H H O O Reactants Products H H H H O O 4 Hydrogen 2 Oxygen

73. Coefficients, the numbers placed in front of formulas to balance equations, indicate the number of particles present in the reaction. If a number is not present it is understand that 1 is the coefficient. 2 H 2 + O 2  2 H 2 O

74. 2 Notice that the number of hydrogen and oxygen atoms are equal 2 The number of oxygen atoms are not the same so the equation is balanced with coefficients.

75. The same number of each kind of atom must be on the left side of the arrow as are on the right side when an equation is balanced. Al OOOOOO

76. OOOOOO When an equation is balanced the number of reactant atoms will always equal the number of product atoms and atoms are conserved Al OOO OOO

77. Chemical Equations Many times it may seem that things we use disappear over time. For example, gasoline in the car. Elements of gasoline are merely re-arranged through a chemical reaction. Gasoline  CO 2 and H 2 O The number of each type of element and their masses remain unchanged (balanced) in a chemical reaction. (Law of Conservation of Mass) A chemical equation is a way to describe or represent what goes on in a chemical reaction and follows the Law of Conservation of Mass. Matter cannot be created or destroyed – ONY rearranged into different substances.

78. Chemical and Physical Change

79. Organic Compounds Compounds that includes CARBON along with other element(s) hydrogen, nitrogen, phosphorous, and or sulfur. Nucleic Acid (DNA), Carbohydrates, Proteins, & Starch.

80. Is it Organic? C 6 H 12 O 6 Ca 3 Si 2 O 7 NaCl C3H8C3H8 Fe 2 O 3 YES no YES no C 5 H 11 NO 2 S CuSO 4 CH 3 COOH Ca 5 (PO4) 3 OH C 27 H 46 O YES no YES no YES

81. The transfer of energy from the sun to producer to primary consumer to secondary consumer to tertiary consumer can be shown in a FOOD CHAIN.

82. The arrow shows the flow of energy, first from the sun to the producers and then to each organism in the food chain.

83. Food Webs: Are interconnected food chains They show the feeding relationships in an ecosystem Arrows point in direction of energy flow

84. Another way of showing the transfer of energy in an ecosystem is the ENERGY PYRAMID.

85. Energy pyramids show That the amount of available energy decreases down the food chain Only 10 % of the energy is passed to the next level It takes a large number of producers to support a small number of primary consumers It takes a large number of primary consumers to support a small number of secondary consumers 100% 10% 1%.1%

87. What is density? Density is a comparison of how much matter there is in a certain amount of space.

88. What is density? Density = mass OR mass ÷ volume. volume Units for density: g cm 3 OR g mL ALWAYS REMEMBER UNITS!

89. Density Problems Frank has a paper clip. It has a mass of 9 g and a volume of 3 cm 3. What is its density? Frank also has an eraser. It has a mass of 3 g, and a volume of 1cm 3. What is its density? D = m v D = 9 g 3 cm 3 D = 3 g/cm 3 D = m v D = 3 g 1 cm 3 D = 3 g/cm 3

90. Jack has a rock. The rock has a mass of 6 g and a volume of 3 cm 3. What is the density of the rock? Jill has a gel pen. The gel pen has a mass of 8 g and a volume of 2 cm 3. What is the density of the pen? D = m v D = 6 g 3 cm 3 D = 2 g/cm 3 D = m v D = 8 g 2 cm 3 D = 4 g/cm 3

91. Al ’ Licia has a watch. It has a mass of 4 g and a volume of 2 cm 3. What is the density of the watch? Mia has a wallet. It has a mass of 15 g and a volume of 5 cm 3. What is the density of the wallet? D = m v D = 4 g 2 cm 3 D = 2 g/cm 3 D = m v D = 15 g 5 cm 3 D = 3 g/cm 3

92. √ Check your understanding Use your Periodic Table

93. 1. The symbol for carbon is – ACa Bc CCA DC

94. 2. How many protons are in an atom of sodium? A 11 B12 C23 D34

95. 3.How many neutrons are there, if the mass number is 1 and the atomic number is 1? A 3 B2 C1 D0

96. 4.How many electrons are in an atom of Cl? A17 B18 C35 D0

97. 5.Which of the following is a chemical formula? A H BO CH 2 O D h2o

98. 6.How many different elements are in baking soda, NaHCO 3 ? A6B5C4D3A6B5C4D3

99. 7. Which of the following situations contains an example of a chemical reaction? AIce forming after water is placed in a freezer BWatercolor paint drying on paper CA sugar cube dissolving in a glass of water DA bicycle rusting after it is left in the rain

100. C 6 H 12 O 6 + 6 O 2  6 H 2 O + 6 CO 2 HCl + NaOH  H 2 O + NaCl 8. Based on the data above, which statement is not true about chemical equations? A. Products are the rearrangement of atoms from the reactants. B.There are always more atoms on the reactant side of the equation than the product side. C.The types of atoms in the products will be the same as the types of atoms in the reactants. D.The mass and number of reactant atoms always equals the mass and number of product atoms.

101. 9. Which chemical reaction is balanced? A.C + O 2  2 CO 2 B.2 C + O 2  2 CO 2 C.2 C + 2 O 2  2 CO 2

102. 10. Which chemical reaction is balanced? A.HBr + Mg  H 2 + MgBr 2 B.2 HBr + Mg  H 2 + MgBr 2 C.2 HBr + 2 Mg  H 2 + 2 MgBr 2