Physical Science Q2, U4: Chemical Bonding (This unit builds student capacity to engage Keystone Biology Eligible Content.)

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1 Physical Science: Term 2, Unit 4 Topic: Chemical Bonding Duration: Traditional (50 minute periods) : days (adjust using professional discretion) Block (90 minute periods) : 6-8 days (adjust using professional discretion) Eligible Content This is what the State of Pennsylvania wants your students to know and be able to do by the end of the unit. CHEM.A.1.2.5: Describe how chemical bonding can affect whether a substance dissolves in a given liquid. CHEM.B.1.4.1: Recognize and describe different types of models that can be used to illustrate the bonds that hold atoms together in a compound (e.g., computer models, ball-and-stick models, graphical models, solid-sphere models, structural formulas, skeletal formulas, Lewis dot structures). CHEM.B : Utilize Lewis dot structures to predict the structure and bonding in simple compounds. A.2.1.1: Describe the unique properties of water [and how these properties support life on Earth (e.g., freezing point, high specific heat, cohesion)]. A.2.2.1: Explain how carbon is uniquely suited to form biological macromolecules. A.2.2.2: Explain how biological macromolecules form from monomers. A.2.2.3: Compare and contrast the structure and function of carbohydrates, lipids, proteins, and nucleic acids in organisms. Performance Objectives These are examples, created by SDP teachers, of how you may translate the eligible content into learning goals for your classroom. SWBAT draw Lewis dot structures (up to the first 20 elements) IOT explain how bonds represent valence electrons and store energy.. SWBAT contrast ionic and covalent compounds and their resulting properties IOT explain the relationship between the physical properties of a substance and its molecular or atomic structure. SWBAT identify the chemical formulas of simple inorganic compounds IOT interpret the meaning of a simple chemical reaction. SWBAT diagram the nature of polar molecules and hydrogen bonding IOT explain the unique properties of water and its importance to living things. SWBAT classify the formation of compounds and their resulting properties using bonding theories (ionic and covalent) IOT explain the relationship between the physical properties of a substance and its molecular or atomic structure. SWBAT distinguish between formulas of molecular compounds and ionic compounds IOT explain the patterns in bonding resulting from the position of elements on the periodic table. SWBAT describe how carbon atoms bond covalently and hydrogen bonds occur between and within molecules forming organic compounds IOT explain the complexity of the 4 major types of organic compounds: carbohydrates, proteins, lipids and nucleic acids.

2 Key Terms and Definitions Amino Acid: any one of 20 different organic molecules that contain a carboxyl and an amino group and that combine to form proteins. ATP (Adenosine Triphosphate): a large molecule that is used inside all cells to store energy (makes bonds by adding a phosphate group) OR release energy (breaks bonds releasing a phosphate group) Bond Length: the distance between two bonded atoms at their minimum potential energy; the average distance between the nuclei of two bonded atoms. Bond Angle: the angle formed by two bonds to the same atom. Carbohydrate: the fuel of life; organic compound that is made of carbon, hydrogen, and oxygen in the ratio 1:2:1; used by cells to make ATP Ex: glucose and fructose both are C 6 H 12 O 6 but have different structural arrangements Chemical formula: shows how many atoms of each element are in a unit of a substance. ex: Aluminium sulfate has the chemical formula Al 2 (SO 4 ) 3, indigo C 16 H 10 N 2 O 2, glucose C 6 H 12 O 6 (Holt, 2004, p.41). Covalent Bond: a bond formed when atoms share one or more pairs of electrons. Empirical Formula: the composition of a compound in terms of the relative numbers and kinds of atoms in the simplest ratio. Ex: CH 2 O is the empirical formula of glucose C 6 H 12 O 6 Glucose: C 6 H 12 O 6 Hydrogen Bond: the intermolecular force occurring when a hydrogen atom that is bonded to a highly electronegative atom of one molecule is attracted to two unshared electrons of another molecule. Ionic Bond: a bond formed by the attraction between oppositely charged ions Ionic Compound: a compound formed from ionic bonding, the attraction between two oppositely charged ions. Metallic Bond: a bond formed by the attraction between positively charged metal ions and the electrons around them. Molecular Compound: a compound formed from covalent bonding, the attraction between two chemically unstable atoms that share valence electrons. Molecular Formula: a chemical formula that shows the number and kinds of atoms in a molecule, but not the arrangement of the atoms (this term can be used synonymously as chemical formula). Ex: molecular formula of aspirin is C 9 H 8 O 4. Monomer: a simple molecule that can combine with other like or unlike molecules to make a polymer. Polyatomic Ion: an ion made of two or more atoms (OH - +, NH 4 ) Polymer: a large molecule that is formed by more than five monomers, or small units. Protein: an organic compound that is made of one or more chains of amino acids and that is a principal component of all cells. Structural Formula: a formula that indicates the location of the atoms, groups, or ions relative to one another in a molecule and that indicates the number and location of chemical bonds. Ex of structural formulas:

3 Starting Points An overview of how the content and skills of this unit connect to students' prior knowledge. Students should already know that atoms (elements) bond together to form compounds. In this unit students will learn that there are different types of bonds that form compounds with different properties depending on the strength and nature of their bonds. In addition students will learn that all bonds are a result of electrostatic attractions between particles. Students should already know from various models that the structures of compounds can take on different shapes. In this unit students will learn to predict the shapes of simple molecules based on the VSEPR theory while utilizing Lewis Dot Structure modeling. Students should already know some basic chemical formulas (H 2 O, NaCl, etc). In this unit students will learn how to distinguish between the empirical formulas and molecular formulas of substances as well as predict the chemical formulas of compounds using information from the periodic table and experimental data. Students should already know that living things contain complex substances such as DNA, proteins, etc. In this unit students will learn to compare and contrast the various macromolecules present in living things and explain why their structures are complex. Instructional Resources Aligned with Performance Objectives and related Key Terms Learning activities and resources targeted to the eligible content of this unit. 1. SWBAT draw Lewis dot structures (up to the first 20 elements) IOT explain how bonds represent valence electrons and store energy. a. Bond Angle b. Bond Length c. Molecular Formula 2. SWBAT contrast ionic and covalent compounds and their resulting properties IOT explain the relationship between the physical properties of a substance and its molecular or atomic structure. a. Ionic Bond b. Ionic Compound c. Covalent Bond 3. SWBAT identify the chemical formulas of simple inorganic compounds IOT interpret the meaning of a simple chemical reaction. a. Chemical Formula b. Empirical Formula c. Structural Formula 4. SWBAT diagram the nature of polar molecules and hydrogen bonding IOT explain the unique properties of water and its importance to living things. a. Hydrogen Bond b. Metallic Bond c. Polyatomic Ion 5. SWBAT classify the formation of compounds and their resulting properties using bonding theories (ionic and covalent) IOT explain the relationship between the physical properties of a substance and its molecular or atomic structure. a. 6. SWBAT distinguish between formulas of molecular compounds and ionic compounds IOT explain the patterns in bonding resulting from the position of elements on the periodic table. a. 7. SWBAT describe how carbon atoms bond covalently and hydrogen bonds occur between and within molecules forming organic compounds IOT explain the complexity of the 4 major types of organic compounds: carbohydrates, proteins, lipids and nucleic acids.

4 a. Amino acid b. ATP c. Carbohydrate d. Glucose e. Monomer f. Polymer g. Protein Resources CK-12 Resources Ionic Compounds RST Molecular Compounds RST Hydrogen Bonding RST Glucose and ATP Other Polarity of water: TEDEd Lesson - How polarity makes water behave strangely - Christina Kleinberg RST Bonding as Tug of War of Electrons, Ionic bonds: TEDEd Lesson - How atoms bond - George Zaidan and Charles Morton RST , WHST Organic Molecules Textbook References Dobson, K., Holman, J., & Roberts, M. (2004). Science spectrum: Physical science. Austin, TX: Holt, Rinehart and Winston. Chap. 5 The Structure of Matter, pgs Johnson, G. B., & Raven, P. H. (2004). Biology. Orlando, Fl: Holt Rinehart and Winston. (Holt Biology) p p Holt Resources (Ch.5) Cross Content Reading, Minilab, Answer Key in PDF TE2OGFhMjBhYjM4 Essential Questions 1. In what ways does understanding the behavior of atoms help us understand how compounds form? 2. How does understanding the nature of bonds within a compound impact the technological significance of that compound? [i.e. the use of complex covalently bonded structures such as hydrocarbons in fuels and plastics vs. the ionically bonded compounds such as acids, bases and salts that are used in other industries.] PA Standards These are the PA Standards that underlie the Eligible Content in this unit A2: Compare and contrast different bond types that result in the formation of molecules and compounds. 3.1.B.A.2: Explain why many biological macromolecules such as ATP and lipids contain high energy bonds. Common Core Standards for Science and Technical Subjects These are Common Core Standards that are related to the Eligible Content in this unit. RST Translate quantitative or technical information expressed in words in a text into visual form and translate information expressed visually or mathematically into words.

5 WHST Conduct short as well as more sustained research projects to answer a question (including a self-generated question) or solve a problem; narrow or broaden the inquiry when appropriate; synthesize multiple sources on the subject, demonstrating understanding of the subject under investigation. WHST Draw evidence from informational texts to support analysis, reflection and research. Next Generation Science Standards These are Next Generation Science Standards that are related to the Eligible Content in this unit. HS-PS1-1 Use the periodic table as a model to predict the relative properties of elements based on the patterns of electrons in the outermost energy level of atoms. [Clarification Statement: Examples of properties that could be predicted from patterns could include reactivity of metals, types of bonds formed, numbers of bonds formed, and reactions with oxygen.] [ Assessment Boundary: Assessment is limited to main group elements. Assessment does not include quantitative understanding of ionization energy beyond relative trends. ] HS-PS1-3 Plan and conduct an investigation to gather evidence to compare the structure of substances at the bulk scale to infer the strength of electrical forces between particles. [Clarification Statement: Emphasis is on understanding the strengths of forces between particles, not on naming specific intermolecular forces (such as dipole-dipole). Examples of particles could include ions, atoms, molecules, and networked materials (such as graphite). Examples of bulk properties of substances could include the melting point and boiling point, vapor pressure, and surface tension.] [ Assessment Boundary: Assessment does not include Raoult s law calculations of vapor pressure. ] HS-PS2-6 Communicate scientific and technical information about why the molecular-level structure is important in the functioning of designed materials.* [Clarification Statement: Emphasis is on the attractive and repulsive forces that determine the functioning of the material. Examples could include why electrically conductive materials are often made of metal, flexible but durable materials are made up of long chained molecules, and pharmaceuticals are designed to interact with specific receptors.] [ Assessment Boundary: Assessment is limited to provided molecular structures of specific designed materials. ]

6 Sample Question from PDESAS Assessment Creator, Diagnostic Section: Chemistry 1. 2.The bonds in BaO are best described as (1) covalent, because valence electrons are shared (2) covalent, because valence electrons are transferred (3) ionic, because valence electrons are shared (4) ionic, because valence electrons are transferred Biology Keystone Release Items: 1. BIO.A Which statement correctly describes how carbon s ability to form four bonds makes it uniquely suited to form macromolecules? (Ans: B, although, A and C are compelling.) A. It forms short, simple carbon chains. B. It forms large, complex, diverse molecules. C. It forms covalent bonds with other carbon atoms. D. It forms covalent bonds that can exist in a single plane. 2. Standard BIO.A Carbohydrates and proteins are two types of macromolecules. Which functional characteristic of proteins distinguishes them from carbohydrates? (Ans. B) A. large amount of stored information B. ability to catalyze biochemical reactions C. efficient storage of usable chemical energy D. tendency to make cell membranes hydrophobic 3. Standard BIO.A Proteins are a major part of every living cell and have many different functions within each cell. Carbohydrates also perform numerous roles in living things. Describe the general composition of a protein molecule. (Ans: students should explain how amino acids link together to form proteins and how they link amine(nh 3 +) to carboxyl ends (COOH-).)

7 This question serves to check for understanding. It is not from released items; however, builds capacity to engage them: 1. Analyze this molecule by contrasting the number of elements to the number of atoms. 2. Explain how you know this is NOT a carbohydrate. 3. Do you think the bonds in this molecule are covalent or ionic? Defend your answer. This question serves to check for understanding. It is not from released items; however, builds capacity to engage them: There are several hundred amino acids, but below is a chart of 20 common amino acids that link together to make proteins. 1. Analyze these amino acids by contrasting the number of elements to the number of atoms.

8 2. Explain how you know they are NOT carbohydrates. 3. Do you think the bonds in these molecules are covalent or ionic? Defend your answer. 4. Try to bind 4 of these amino acids together to start making a protein. How would you do it? Answers: 1. Using glycine as a reference: 2 carbons atoms, 2 oxygen atoms, 5 hydrogen atoms, 1 nitrogen atom = 10 total atoms yet only 4 elements total. 2. This is not a carbohydrate because the C:H:O ratio is not 1:2:1; also, it contains N. 3. The bonds are likely polar covalent because I see the + on the N. Also, carbon tends to form covalent bonds, not ionic bonds. Lastly, the atoms bonded in this amino acid are all located closely on the periodic table, which contra-indicates for ionic bonding (they all have similar electronegativities, so none of them is ripping electrons from the other). 4. The positive ends (H 3 N + ) are attracted to the negative ends C=OO -. They add by dehydration synthesis a process of bonding where H 2 O is lost (dehydration) to yield a bond (synthesis).

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