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Honors Biology Chapter 2 Chemistry. DRY ERASE ATOM ATTITUDE Everyone gets a dry erase board, dry erase pen, and tissue for erasing. The teacher will ask.

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Presentation on theme: "Honors Biology Chapter 2 Chemistry. DRY ERASE ATOM ATTITUDE Everyone gets a dry erase board, dry erase pen, and tissue for erasing. The teacher will ask."— Presentation transcript:

1 Honors Biology Chapter 2 Chemistry

2 DRY ERASE ATOM ATTITUDE Everyone gets a dry erase board, dry erase pen, and tissue for erasing. The teacher will ask you a question about atomic structure, you will write your answer and hold up your board.

3 Are you wondering why we are learning chemistry in biology class? All of our cells are made of chemical compounds. All the activities of our bodies work on chemical reactions. All of our body’s reactions use water. Such as neurotransmitters affecting neurons

4 MATTER Anything that occupies space (VOLUME) and has MASS Is air matter? Yes

5 Match as energy (capacity to do work) or matter (occupies space and has mass) Water Electricity Air Helium Sunlight Iron Carbon Matter Energy Matter Energy Matter

6 2.1 ELEMENTS, ATOMS, COMPOUNDS (are matter)


8 YOU NEED TO KNOW The Names (spelled correctly) and the Symbols (written correctly) on p. 18 (Table 2.1) “Elements in the Human Body” 25 elements (includes trace elements) QUIZ on FRIDAY Sept. 27

9 ELEMENTS Substance that cannot be broken down to other substances by ordinary chemical means (heating, adding an acid…) YouTube - ?Tom Lehrer's The Elements" animated?? ****ASAP SCIENCE Periodic Table In Order OR YouTube - ?The Elements Animation??YouTube - ?The Elements Animation??

10 Where can you find an element? The Periodic Table of the Elements – see Appendix 2 and get your personal copy

11 ELEMENTS AND SYMBOLS: Ca, H, Li, O, C, Mg What rules apply to writing the symbols (abbreviations of the elements)? First letter capital, second letter is lower case What are the four most common elements in the human body? (see chart) CHON What are trace elements? Less than 0.01% of human body weight

12 Which are elements? Cu C CO N NO WHY? Cu C N only one kind of matter Gold - Au

13 COMPOUNDS Substance of two or more different atoms chemically combined in a fixed ratio EXAMPLES: CO 2 H 2 SO 4 H 2 O CO How is a compound written differently than an element? More than one kind of element (more than one capital letter). NOTE: H 2 is not a compound – its an element (Only one kind of element) Subscripts (tell how many atoms there are)

14 Formula Formula is the abbreviation for a compound. CO 2 H 2 SO 4 H 2 O Carbon dioxide sulfuric acid water What rules seem to apply to writing a formula? Capital letters for elements Subscript number behind and just below the line of what element it represents

15 Which are compounds? Na N H 2 NO 2 H 2 O Why? NO 2 H 2 O 2 or more different elements chemically joined (2+ diff. capital letters)

16 Which are symbols? Abbreviations for elements C CO 2 Mn CO Ni Why? C Mn Ni Only one capital letter

17 What’s the difference? Co CO co Symbol formula nothing

18 Which are formulas? Abbreviation for a compound H 2 SO 4 Cl 2 H 2 0 Al Why? H 2 SO 4 H 2 0 abbreviations for compounds (2 or more different kinds of elements)

19 Can you figure out the difference between a mixture and a compound? A mixture is two or more elements (or compounds) NOT chemically joined. A compound is two or more atoms chemically joined. Do Worksheet: Elements, Compounds, Mixtures

20 DO WORKSHEET: Elements, Compounds, Mixtures (back of Atomic Mass and Atomic Number Worksheet) Work in groups of three, then we’ll compare answers.

21 2.2 What are trace elements? Needed in the body in only small amounts Like mg (milligrams) WHY IMPORTANT IF WE DON’T NEED SO MUCH? Minerals act as catalysts (speed up reactions) for many biological reactions

22 Trace Elements Needed by some organisms but only in very small amounts Like iodine, we need only 0.15 mg per day A deficiency will cause a goiter

23 Trace Elements Fluorine – in drinking water, toothpaste (help dental decay) But too much can cause fluorosis (white chalky build- up)

24 Trace Elements Iron Rich Foods Most important use is to carry oxygen in the blood

25 2.3 Atoms: protons, neutrons, electrons Do you know what these particles are?

26 2.3 Atoms: protons, neutrons, electrons Do you know what these particles are? Protons Neutrons Electrons

27 Basic Atomic Structure Youtube (1:57)Basic Atomic Structure Youtube

28 Atom Smallest unit of matter that retains the properties of the element Li Na

29 Which shows one atom? C N N 2 H 2 0 Why? C and N only one in number Which are elements? C N N 2

30 Molecule Two or more atoms held together by chemical bonds

31 Which are molecules? Co CO CO 2 O 2 Why? CO CO 2 O 2 two or more atoms (alike or not alike, it doesn’t matter) bonded together

32 Where is each subatomic particle located? Proton in the Neutron nucleus Electron-outside the nucleus

33 What is the charge of each subatomic particle? Proton Neutron Electron + O _ positive none negative

34 What is the relative size? Proton neutron electron 1 amu 1 amu ~1/2000 amu AMU = atomic mass unit = 1/12 CARBON ATOM


36 Neutral Atoms (no charge) (as seen on the periodic table) 39 Mass Number p + n K Symbol 19 Atomic Number p (electrons = number of protons) Neutral if negative charges = positive )

37 How can you tell the mass number and atomic number?

38 When looking on the periodic table… Atomic Number In order Identify element by its number of protons Mass Number A decimal (average of masses of all isotopes of that element)

39 Isotopes of Carbon What is the mass number decimal? 12.011 What would you round it to? 12

40 What is the atomic number of? Silicon fluorine sodium WHY? 14 9 11 Number in succession (not a decimal) Number of protons

41 What is the mass number of…? Carbon nitrogen hydrogen WHY? 12 14 1 Decimal number on periodic table Not other number in succession Number of p + n

42 How do you find the number of…? Protons electrons neutrons Atomic atomic mass number number number minus atomic no. (if neutral)

43 How many? Protons electrons neutrons Carbon 6 6 6 Chlorine 17 17 18

44 What is the atomic number? Mass Number? Number of p? Number of e-? Number of n?

45 Do Atomic Mass and Atomic Number WORKSHEET Collaborate with your partner next to you, then we’ll see what’s right.

46 Isotope isotope animation Atoms that differ in number of neutrons Also differ in mass number (since it is p+n) 41 Note more n K 19 Note same p

47 Isotope Examples

48 Which is the neutral Li? Which are the isotopes of Li?

49 Neutral – see periodic table

50 Which are isotopes? 16 20 38 128 12 O F K I C 8 9 19 53 6 WHY? 32 P 15 NOTE: you are looking for a different number of neutrons than the elements found on the periodic table.

51 Which are isotopes? 16 20 38 128 12 O F K I C 8 9 19 53 6 WHY? 20 38 128 F K I 9 19 53

52 Which are isotopes? 16 20 38 128 12 O F K I C 8 9 19 53 6 WHY? 20 38 128 F K I 9 19 53

53 2.4 Radioactive Isotopes An isotope that decays spontaneously to emit (give off) particles or energy Here a radioisotope is used to examine a thyroid gland

54 Uses of Radioisotopes C-14 dating (can date living things up to 6,000 years old) Carbon Dating (2:00 mins) or Carbon Dating Nuclear Medicine: What to expect (2:46 mins)Nuclear Medicine: What to expect Bozeman Biology Radioactive Dating (9 mins)Bozeman Biology Radioactive Dating Carbon-14 Dating (2 mins)Carbon-14 Dating Thyroid tumor Highlight parts of the body for diagnosis PET SCAN: detect tumors, weak spots in arteries

55 Uses of Radioisotopes Iodine-131 PIB molecule to treat thyroid cancer detect Alzheimers PET scan

56 Negative Effects of Nuclear Radiation Chernobyl Nuclear Plant Accident

57 Negative Effects of Radon Radon, a radioactive gas, causes lung cancer Found in regions containing uranium

58 2.5-2.7 Chemical Bonds

59 Ion Charged atom Differs in number of electrons 39Same mass number K+ means lost one electron 19 Same atomic number

60 ION Charged atom Na + (has lost one electron) O -2 (has gained two electrons) Shown with superscript +/- and number on upper right (can omit number if a “1”)

61 Cation Positive ion Na + Mg +2 Lost electrons Anion Negative ion Cl - O -2 gained electrons

62 If one electron is… Lost what charge will the ion have? +1 11p+ 11 e- 11p+ 10e-

63 Which are ions? Cl O -2 Na +1 N 2 Why? O -2 Na +1 Charged atoms (lost or gained electrons) show charges as superscripts

64 Valence Electrons Outer shell electrons Bonding capacity of an atom

65 How do electrons arrange themselves in an atom… In the outer electron shells (energy levels)? They are full with 2, 8, 8 Fill inner shell first, then go to next shell out (Outermost shell has the greatest energy) Click on animation, scroll down

66 Get kinda complicated beyond 2,8,8…so that’s all we’ll do for now!

67 Which electrons determine… The chemical properties of the atom? Outermost shell

68 If one electron is gained… What charge will the ion have?

69 If 2 electrons are lost… What charge will the ion have? +2 If two electrons are gained… What charge will the ion have? -2

70 Filled outer e- shells How many e- fill the first shell (nearest the nucleus)? How many e- fill the next two shells? nucleus

71 Gain 1 e- or lose 7 e-? If gains 1 e-, then it becomes -1

72 Gain 7 e- or lose 1 e-? If loses 1 e-, the it becomes +1.

73 Gain or Lose ? If it could as easily lose or gain e-, then it will probably share them. It will form a covalent bond. Tutorial 2.1 Chemical Bond Formation

74 Fill in the chart of e- ElementNumber of e- First shellSecond Third Shell carbon12 lithium3 Sodium11 Oxygen16

75 Fill in the chart of e- ElementNumber of e- First shellSecond Third Shell carbon624 lithium321 Sodium1128 1 Oxygen826

76 How are ion charges determined? Cation = positive (+) ion Anion = negative (-) ion

77 How are ion charges determined? If lose 1 e- = +1 charge If gain 1 e- = -1 charge If lose 2 e- = +2 charge If gain 2 e- = -2 charge

78 Periodic Table Hint: You can tell how many electrons are in an atom’s outermost shell by just looking at its position on the periodic table!!!!!

79 Note any pattern of valence electrons (outer shell) as they appear in the periodic table?

80 +1 +2 share -3 -2 -1 0 e- in outer shells Ion formed e- in outer shell Full outer e- shells H 8

81 How many electrons in each shell? (atomic number is given) Carbon oxygen fluorine sodium 12 16 9 11 2,4 2,6 2,7 2,8,1

82 Now let’s do the Drawing Atoms Worksheet (and next 4 slides) How the electrons fill their shells (link)How the electrons fill their shells 1 st shell – 1 pair 2 nd shell – e- space far apart, singles, then pair 3 rd shell – e- space far apart, singles, then pair


84 Bohr Diagram Let’s do carbon (6 electrons) 1. Draw a nucleus. 2. Draw the number of rings needed. 3. Start in the first shell- only 2 e-, paired (put next to each other) C

85 1 2 3 4

86 1 2 3 4 5 6

87 Now do on the Atomic Structure Worksheet

88 See the trend of how electrons fill the valence shells Lewis dot structures Octet Rule – electrons fill a shell until it’s full with 8 electrons Atoms are most stable with a filled outer electron shell

89 What do we call the forces that… Hold atoms together in a molecule? Chemical bonds…not to be confused with James Bond

90 Why do atoms bond? To have filled outer electron shells! Atom Heaven

91 What is a chemical bond? Attraction between two or more atoms due to opposite charges YouTube - ?Ionic and covalent bonding animation??YouTube - ?Ionic and covalent bonding animation??

92 Bonding Covalent share electrons Ionic transfer of electrons (lose or gain)

93 IONIC BOND An atom may lose one or more electrons and become positive (+) An atom may gain one or more electrons and become negative (-) The (+) and (-) ions formed now attract each other and form an ionic bond.


95 Covalent Bonds Click HERE: Polar Covalent Bonding (3 animations)Polar Covalent Bonding Electrons are shared Usually if near the same number of e- in outer shells

96 Covalent bonding can be shown as: Bohr model Electron-dot Structural Formula

97 Covalent Bonding Even sharing Uneven sharing

98 Writing Bonds Each “ –” is equal to “ : “ or “two electrons”Each “ –” is equal to “ : “ or “two electrons” Single C – C or C:C Double C = C or C::C Triple C= C or C:::C

99 Different Ways to Represent Four Common Molecules butane

100 LET’S REVIEW: Which atoms combine… with other atoms? Ones that do not have filled outer electron shells

101 REVIEW: What is the driving force to make atoms join with other atoms to form compounds? TO HAVE FILLED OUTER ELECTRON SHELLS!!!!!!!!!!!!!!!!!!!!!!!!

102 REVIEW: How does an atom… Get a filled outer electron shell? Gaining, losing, or sharing electrons



105 What do you notice about the ion charge and the subscripts?

106 Do the Flip-Flop So you can cancel out the (+) and (-)

107 If there is only one atom, you do not need to write a “1” You can reduce the subscripts if they are the same: Fe +2 O -2 Fe 2 O 2 reduce to FeO

108 Electronegativity "power of an atom in a molecule to attract electrons to itself." Electronegativity only has meaning in a bond.

109 Electronegativity Tendency of an atom to attract electrons towards itself and thus the tendency to form negative ions.

110 Electronegativities H = 2.1 O=3.5 C=2.5 H-H = 0.0 bond pure covalent O-H bond = 1.4 polar (3.5-2.1) covalent NaCl = 2.1 ionic

111 Electronegativity The more electronegative atom pulls shared electrons toward its nucleus. NONPOLAR – equal sharing of electrons POLAR – unequal sharing of electrons

112 IONIC BOND What makes up ionic bonds? IONS WHY? Opposite charged ions attract

113 Making ionic bond in NaCl YouTube - ?Ionic and covalent bonding example?? YouTube - ?Reaction of Sodium & Chlorine (with subtitles)??

114 SALT = Synonym for an ionic compound Not just NaCl Iron SulfideCopper Sulfate Sodium chloride

115 Covalent Bond What makes up covalent bonds? Atoms that are sharing electrons

116 Covalent Bonds Polar Covalent Unequal sharing of e- Nonpolar Covalent Equal sharing of e-

117 Valence Shells Only Shown

118 How can they be written? Single bond double bond triple bond C-C C=C C=C C:C C::C C:::C 2 e- 4 e- 6 e-

119 Contrast YouTube: Ionic and Covalent Bonding animationYouTube: Ionic and Covalent Bonding animation

120 Molecule A group of two or more atoms held together by covalent bonds

121 Comparing Bonds IONIC BOND (gain or lose e-) COVALENT BOND (sharing e-)

122 What’s the difference between Intramolecular and Intermolecular Forces?


124 What’s the difference? Intermolecular attractions are between one molecule and a neighboring molecule (Van der Waals, hydrogen bonds) USUALLY WEAKER Intramolecular attractions are the forces which hold an individual molecule together (for example, the covalent bonds or ionic bonds). USUALLY STRONG


126 INTERMOLECULAR FORCES A. H-bonds (in water and DNA) B. van der Waals- “dispersion” (in tertiary protein structures) C. Disulfide bridges (in tertiary protein structures)

127 INTERMOLECULAR FORCES A. H-bonds (in water and DNA) B. van der Waals- “dispersion” (in tertiary protein structures) C. Disulfide bridges (in tertiary protein structures)

128 Hydrogen Bonds attractive force between the hydrogen (partial + charge) attached to an electronegative atom of a different (oxygen, nitrogen, or fluorine) (has a partial negative charge. Hydrogen Bond Animation Hydrogen Bond Animation

129 Hydrogen Bonds: Intermolecular between H and F, O, or N

130 Hydrogen Bonds In Water – between O- and H+ In DNA – between bases

131 van der Waals Van der Waals Dispersion Forces are momentary very weak forces of attraction between nonpolar molecules as they approach each other (opposite charged ends) Like gecko feet on glass Temporary dispersion of electrons make temporary charges

132 Where might you find van der Waals? Water would not condense from vapor into solid or liquid forms if its molecules didn't attract each other. Many properties of molecular compounds, including crystal structures (e. g. the shapes of snowflakes), melting points, boiling points, heats of fusion and vaporization, surface tension, and densities. Gigantic molecules like enzymes, proteins, and DNA into the shapes required for biological activity.

133 Disulfide Bonds: Protein Tertiary Structure Disulfide Bond in Tertiary Protein

134 Disulfide Bonds Disulfide bonds are formed between the side chains of cysteine by oxidation (loss of e-) of two thiol groups (SH) to form a disulfide bond (S- S), also sometimes called a disulfide bridge.

135 THEME OF EMERGENT PROPERTIES New properties that arise with each step upward in the hierarchy or life, owing to the arrangement and interactions of parts as complexity increases. WHOLE IS GREATER THAN THE PARTS

136 How is the emergent property idea apply to a compound and atoms? HINT:

137 2.9 Chemical Reactions The making and breaking of chemical bonds, leading to changes in the composition of matter.

138 Chemical Reactions Reactants on the left of the arrow Products on the right of the arrow IDENTIFY: 2Mg(s) + O 2 (g) → 2MgO(s) MgO(s) + H 2 O(l) → Mg(OH) 2 (s) N 2 (g) + 3H 2 (g) → 2NH 3 (g)

139 Same number of each element on left side as on the right side CH 4 (g) + 2O 2 (g) CO 2 (g) + 2H 2 O (g) ReactantsProducts C = 1 H = 4 O = 4 C = 1 H = 4 O = 4

140 Signs of a Chemical Reaction Precipitate forms Color Change Gas Forms Temperature change

141 Chemical Reaction Example An iron bar rusts. The iron reacts with oxygen in the air to make rust. 4 Fe + 3 O 2 2 Fe 2 O 3

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