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Honors Biology Chapter 2

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1 Honors Biology Chapter 2

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

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??

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

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: CO2 H2SO4 H2O CO How is a compound written differently than an element? More than one kind of element (more than one capital letter). NOTE: H2 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. CO2 H2SO4 H2O
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 H2 NO2 H2O Why? NO2 H2O
2 or more different elements chemically joined (2+ diff. capital letters)

16 Which are symbols? Abbreviations for elements
C CO2 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
H2SO Cl H Al Why? H2SO H20 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 and Molecules

26 Atoms are made of protons, neutrons, electrons
Do you know what these particles are?

27 Answers: Do you know what these particles are? Protons Neutrons

28 Basic Atomic Structure Youtube (1:57)

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

30 C and N only one in number Which are elements? C N N2
Which shows one atom? C N N2 H Why? C and N only one in number Which are elements? C N N2

31 Molecule Two or more atoms held together by chemical bonds

32 Which are molecules? Co CO CO2 O2 Why?
CO CO O2 two or more atoms (alike or not alike, it doesn’t matter) bonded together

33 Where is each subatomic particle located?
Proton in the Neutron nucleus Electron-outside the nucleus Golden Retrievers Show Atomic Structure Youtube (2:11)

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

35 What is the relative size?
Proton neutron electron 1 amu amu ~1/1836 amu AMU = atomic mass unit = 1/12 CARBON ATOM (standard)


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

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

39 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)

40 Why is the mass number a decimal? Average of the Isotopes of Carbon
What is the mass number decimal? 12.011 What would you round it to? 12

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

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

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

44 How many? Protons electrons neutrons Carbon Chlorine

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

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

47 ISOTOPES INTRO Isotopes (Virtual School) (2:51)
Watch the video and list what facts you learned about isotopes. No, not about the Albuquerque Isotopes

48 Isotope Atoms that differ in number of neutrons
Also differ in mass number(since it is p + n) But all have the same number of protons

49 Isotope Examples What are isotopes? (7:56)

50 Which is the most common isotope of Li? (check the periodic table)

51 Why is the Mass Number a Decimal?
Finding the Average Atomic Mass (2:55) Watch this and find out how…

52 How do you write chemical notation for isotopes?

53 2.4 Radioactive Isotopes An isotope that decays spontaneously to emit (give off) particles or energy until it is stable Here a radioisotope is used to examine a thyroid gland Radioactive Tracers in Medicine (3:57)

54 Radioactive Decay Examples

55 Uses of Radioisotopes C-14 dating (can date living things up to 6,000 years old) Carbon Dating (2:00 mins) Technetium 99 Radioisotope (2:58) Nuclear Medicine: What to expect (2:46 mins) Bozeman Biology Radioactive Dating (9 mins) Carbon-14 Dating (2 mins) PET SCAN: detect tumors, weak spots in arteries Highlight parts of the body for diagnosis Thyroid tumor

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

57 Negative Effects of Nuclear Radiation
Chernobyl Nuclear Plant Accident

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

59 Chemical Bonds

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

61 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”) What's and Ion? Youtube (6:52)

62 Ions form by gaining or losing electrons

63 O-2 has gained two electrons
Na has lost an e- so it is Na+1

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

65 +1 If one electron is… Lost what charge will the ion have? 11p+ 11 e-

66 Which are ions? Cl O-2 Na+1 N2 Why? O-2 Na+1
Charged atoms (lost or gained electrons) show charges as superscripts

67 Valence Electrons Outer shell electrons
Determines the bonding capacity of an atom

68 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) Can you see any pattern how the e- arrange themselves?

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


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

72 If one electron is gained…
What charge will the ion have? -1

73 -2 +2 If 2 electrons are lost… What charge will the ion have?
If two electrons are gained… What charge will the ion have? -2

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

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

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

77 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

78 Fill in the chart of e- Element Number of e- First shell Second Third
Shell Shell carbon 6 lithium 3 Sodium 11 Oxygen 16

79 Fill in the chart of e- Element Number of e- First shell Second Third
Shell Shell carbon 6 2 4 lithium 3 1 Sodium 11 Oxygen 8

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

81 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

82 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!!!!!

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

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

85 How many electrons in each shell? (atomic number is given)
Carbon oxygen fluorine sodium 2, , , ,8,1

86 How many valence electrons
How many valence electrons? Will these atoms lose or gain e- and how many?

87 How many valence electrons
How many valence electrons? Will these atoms lose or gain e- and how many? Lose lose O lose share gain lose 1 H He Li C N Na+

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


90 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) Get worksheet C

91 1 2 4 3

92 1 5 2 4 6 3

93 Bohr model electron filling order

94 Are these correct Bohr models?

95 Are these correct Bohr models?
What errors are at the ?

96 Now do on the Atomic Structure Worksheet

97 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

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

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

100 What is a chemical bond? Attraction between two or more atoms YouTube - ?Ionic and covalent bonding animation??

101 Get Bonding Handouts Electronegativities Intermolecular Forces
Bonding Reference Sheet

102 Types of Bonds Intramolecular Intermolecular Within the molecule
-Ionic -Covalent Polar Nonpolar Between different molecules Van der Waals London forces Dipoles Hydrogen Bonds

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

104 IONIC BOND lose one or more electrons become (+)
gain one or more electrons become (-) The (+) and (-) ions formed now attract each other and form an ionic bond.


106 Covalent Bonds Polar Covalent Unequal sharing of e- Nonpolar Covalent

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

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

109 How can covalent bonds be written?
Single bond double bond triple bond C-C C=C C=C C:C C::C C:::C 2 e e e-

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


112 Different Ways to Represent Four Common Molecules

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 Sodium chloride
Copper Sulfate Iron Sulfide

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

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

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


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

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

121 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 O Fe2O2 reduce to FeO

122 Get Electronegativities handout
Electronegativity Get Electronegativities handout

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

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

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

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

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

128 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

STRONGEST BOND WEAKEST BOND Covalent Ionic Hydrogen Van der Waals (dipole-dipole London forces) intramolecular

A. H-bonds (H to F, O, or N) B. van der Waals- temporary “dispersion” London (nonpolar) and dipole-dipole forces (polar) C. Disulfide bridges (-S-S-) Intermolecular Forces Youtube (9:11-if ya got time)

131 Intermolecular Forces video and worksheet
What three types of intermolecular forces are there? What does dipole mean? Why do those molecules attract each other? London forces are in molecules that are not dipoles. What do they do to their e- to cause an attraction? What three possible atoms can make a hydrogen bond with hydrogen? List the forces in order of strength.

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

133 Where Might you find Hydrogen Bonds?
In Water – between O- and H+ In DNA – between bases

134 Intramolecular: Van der Waals
Van der Waals on Gecko Feet (8:22) Is the sum of the attractive forces between molecules (but not H-bonds or covalent bonds)

135 van der Waals Temporary dispersion of electrons make temporary charges
Van der Waals Dispersion Forces Temporary dispersion of electrons make temporary charges

136 Where might you find van der Waals?
crystal structures (e. g. the shapes of snowflakes), DNA shape

137 Intramolecular: (Van der Waal type) Dipole-dipole
exists between neutral polar molecules only when they are close together Dipole Forces Bozeman youtube (7:32) Temporary shift of the electrons to make a partial + and a partial - end

138 Weakest van der Waals: London Dispersion Forces
Temporary polarity between nonpolar atoms or molecules All molecules have them at some time Bozeman London Dispersion Forces (5:02)

139 London Dispersion Force London Dispersion Force Animation

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

141 Disulfide Bonds formed between the side chains of cysteine in a protein SH) to form a disulfide bond (S-S) (Will learn about this in Chapter 3)

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

143 How is the emergent property idea apply to a compound and atoms?

144 2.9 Chemical Reactions The making and breaking of chemical bonds, leading to changes in the composition of matter.

145 Chemical Reactions Reactants on the left of the arrow
Products on the right of the arrow IDENTIFY: 2Mg(s)  +  O2(g)  →    2MgO(s) MgO(s)  +   H2O(l)  →    Mg(OH)2(s) N2(g)  +  3H2(g)  →    2NH3(g)

146 Same number of each element on left side as on the right side
CH4 (g) + 2O2 (g) CO2 (g) + 2H2O (g) Reactants Products C = 1 H = 4 O = 4

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

148 Chemical Reaction Videos
Na and Cl Chemical Rx (52 secs.) Genie in a Bottle Reaction - Steve Spangler (3:36) Weirdest Chem. Rx in the World (2:52) Mercury(II) thiocyanate Hg(SCN)2 The Naked Scientists Videos (MP3)

149 Chemical Reaction Example
An iron bar rusts. The iron reacts with oxygen in the air to make rust. 4 Fe + 3 O2 2 Fe2O3

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