Chemistry 2 nd 6 Weeks

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1 NAME OF UNIT UNIT II ESTIMATED # OF DAYS 2 nd 6 Weeks_ Weeks 1 Weeks 2-3 Weeks 4-5 Components Unit Name IIA: Nuclear Chemistry IIB: Light, Energy, and Periodic Trends IIC: Bonding Short Descriptive Overview This unit explains the processes of radioactivity and radioactive decay, and discusses the characteristics of radioisotopes. This unit uses quantum theory to describe the modern model of the atom and explain atomic emission spectra; it also describes trends in atomic and ionic properties found within the periodic table. This unit discusses how chemical bonds result from the sharing or transfer of valence electrons between pairs of atoms. Properties and forces within these bonds are also examined TEKS 1-A, B, C 2-A, B, C, D, E, F, G, H, I 3-A, B, C, D, E, F (12) Science concepts. The student understands the basic processes of nuclear chemistry. The student is expected to: (A) describe the characteristics of alpha, beta, and gamma radiation; Readiness (B) describe radioactive decay process in terms of balanced nuclear equations; Supporting (C) compare fission and fusion reactions. Readiness 1-A, B, C 2-A, B, C, D, E, F, G, H, I 3-A, B, C, D, E, F (5) Science concepts. The student understands the historical development of the Periodic Table and can apply its predictive power. The student is expected to: (C) use the Periodic Table to identify and explain periodic trends, including atomic and ionic radii, electron gravity, and ionization energy. Readiness (6) Science concepts. The student knows and understands the historical development of atomic theory. The student is expected to: (B) understand the electromagnetic spectrum and the mathematical relationships between energy, frequency, and wavelength of light; Supporting (C) calculate the wavelength, frequency, and energy of light using Planck's constant and the speed of light; Supporting (E) express the arrangement of electrons in atoms through electron configurations and Lewis valence electron dot structures. Readiness (1) A, B, C (2) A, B, C, D, E, F, G, H, I (3) A, B, C, D, E, F (7) Science concepts. The student knows how atoms form ionic, metallic, and covalent bonds. The student is expected to: (C) construct electron dot formulas to illustrate ionic and covalent bonds; Readiness (D) describe the nature of metallic bonding and apply the theory to explain metallic properties such as thermal and electrical conductivity, malleability, and ductility; Supporting (E) predict molecular structure for molecules with linear, trinomial planar, or tetrahedral electron pair geometries using Valence Shell Electron Pair Repulsion (VSEPR) theory. Supporting 1

2 Generalizations/Enduring Understandings Guiding/Essential Questions 1) In nuclear reactions, atomic number and atomic mass are conserved. 2) Each element has its own characteristic decay rate and half-life. 3) Heavy transuranium elements tend to undergo radioactive decay because they are unstable isotopes. 1) What types of radiation are there, and how harmful are they? 2) How is the decay rate of a radioactive substance expressed? 3) What is fission? Fusion? 4) What are some devices used to detect radiation, and how do they function? 1) Light can act as both a wave and a particle and can exhibit properties of both. 2) Electromagnetic radiation has a characteristic frequency and wavelength, which are inversely proportional. 3) Electron configurations represent the location of all of the electrons within an atom or ion. 4) Many properties of an element can be determined based on its location on the Periodic Table. 1) What role do energy and stability play in the way in which electrons are configured in an atom? 2) What causes an element such as neon to emit light when excited by an electric current? 1) Molecule shape is affected by bonding and nonbonding electron pairs. 2) Molecule shapes cause polarity. 3) The strength of intermolecular forces within different substances affects the properties of the substances. 1) What characteristics of sodium and chlorine atoms allow them to form the stable compound sodium chloride, also known as table salt? 2) How many valence electrons does each group in the periodic table have? 3) Why are crystalline solids such stable structures? 4) What property of the bonds between crystal atoms makes them so rigid and brittle? 5) Why are crystals of different ionic compounds different shapes? 6) What property makes metals good conductors? 7) What are the properties of malleable and ductile metals? 8) What is an alloy? 9) How are the bonds in molecules of ordinary oxygen similar to the bonds in molecules of ozone? 10) How does the formation of a coordinate covalent bond differ from that of a covalent bond? 11) How do attractive and repulsive forces influence molecular bonding? 12) How do unshared pairs of electrons influence the shape of a molecule? 13) How do the polar bonds of atoms in water molecules influence the distinctive geometry of snowflakes? 14) What does the term electron gravity mean? 15) Which element is the most electronegative? 2

3 Learning Targets Performance Levels Learning Progression Performance Levels Learning Progression Performance Levels Learning Progression 1) Students will understand to basic processes of nuclear chemistry. 1) Students will derive the formula for Alpha and beta particles knowledge: Students will differentiate the 2) Students will write and balance nuclear reactions. types of radiation and the types of radioactive decay. 3) Students will classify nuclear reactions as fission or fusion Concepts Nuclear Decay Fusion Fission 1) Students will extrapolate the relationship between atomic structure and the periodic table. knowledge: Students will understand how electrons are arranged around the nucleus to describe the organization of the periodic table and periodic trends 2) Students will discover the significance of quantized energies of electrons as they relate to the quantum mechanical model of the atom. knowledge: Students will calculate wavelength, frequency, and energy of a photon of light. Quantum Theory Properties of Waves Light as a Wave 1) Students will apply the Aufbau Principle, the Pauli Exclusion Principle, and Hund s Rule in writing the electron configuration of elements. 2) Students will explain why the electron configurations for some elements are exceptions. 3) Students will calculate the wavelength, frequency, and energy of light. 4) Students will explain the origin of the atomic emission spectrum of an element. 5) Students will predict the properties of an element based on location in the periodic table. 6) Students will use electron configurations to classify elements as noble gases, representative elements, transition metals, or inner transition metals. 7) Students will interpret group trends in atomic radii, ionic radii, ionization energies, and electronegativities. 1) Students will predict they type of bonding that occurs for a given substance. knowledge: Students will determine if a substance is a metal or non-metal. 2) Students will analyze electronegativity values to classify a bond as nonpolar covalent, polar covalent, or ionic. knowledge: Students will describe the electronegativity trend on the periodic table. 3) Students will predict physical properties of covalent molecules based on electron dot structures. Knowledge: Students will draw the electron structure for a simple covalent molecule, then utilize VSEPR theory to predict the shape. Covalent Bonds Ionic Bonds Hydrogen Bonding 1) Students will list the characteristics of an ionic bond. 2) Students will analyze the characteristics of ionic compounds to explain the electrical conductivity of ionic compounds when melted and when in aqueous solutions. 3) Students will apply the theory of metallic bonds to explain the physical properties of metals. 4) Students will describe the arrangements of atoms in some common metallic crystal structures. 5) Students will apply electron dot structures to show the formation of single, double, and triple covalent bonds. 6) Students will name and describe the weak attractive forces that hold groups of molecules together. 3

4 Transmutation Radioactivity Types of Radiation Nuclear Stability Half-Life Light as a Particle Electron Configurations Orbital Notations Lewis Dot Notations Periodic Trends Electronegativity Ionization Energy Atomic Radii Metallic Character Intermolecular Forces VSEPR Shapes Polarity Dipole Properties of Water Metallic Bonding Network Solid Crystal Lattices and Ionic Bonds Topics 1) Isotopes with unstable nuclei are radioactive and are called radioisotopes. The nuclei of radioisotopes emit radiation as they decay to stable nuclei. 2) The radiation may be alpha (positively charged helium nuclei), beta (electrons), or gamma (electromagnetic radiation). 3) Every radioisotope decays at a characteristic rate. A half-life is the time required for one-half of the nuclei in a radioisotope to decay. 4) In fission, isotopes split when bombarded with neutrons. The isotopes release neutrons that cause a chain reaction. 5) In fusion, light nuclei fuse to make more massive nuclei. 6) Radioactivity and radiation are used extensively in agricultural research, in medical diagnosis, and in the treatment of some diseases. 1) The energies of electrons in an atom are quantized in the modern quantum mechanical model of the atom. 2) Current theory predicts the probability of finding an electron in terms of a cloud of negative charge. The atomic orbital, or regions in which electrons are likely to be found, can be calculated from a mathematical expression. 3) The ways in which electrons are arranged around the nuclei of atoms are called electron configurations. 4) Correct electron configurations for atoms may be written using the Aufbau Principle, the Pauli Exclusion Principle, and Hund s Rule. 5) For all electromagnetic waves, the product of frequency and wavelength always equals the speed of light. 6) The concept of quantized electron energy levels in atoms grew out of the study of the interaction of light and matter. 7) The line emission spectra f atoms are best explained by quantized energy levels. 8) Elements that have similar properties also have similar electron configurations and are members of the same group. 9) The atoms of the noble gas elements have filled outermost s and p sublevels. 10) The outermost s and p sublevels of the representative elements are only partially filled. 11) The outermost s and nearby d sublevels of transition metals contain electrons. 12) The outermost s and nearby f sublevels of inner transition metals contain electrons. 13) Regular changes in the electron configuration of 1) Atoms in a compound are held together by chemical bonds. Chemical bonds result from the sharing or transfer of valence electrons between pairs of atoms. 2) Bonded atoms attain the stable electron configuration of a noble gas. The noble gases themselves exist as isolated atoms because that is their most stable condition. 3) For the representative elements, the number of valence electrons is equal to the element s group number in the periodic table. 4) The transfer of one or more valence electrons between atoms produces positively and negatively charged ions, or cations and anions, respectively. 5) The attraction between an anion and a cation is an ionic bond. A substance with ionic bonds is an ionic compound. 6) Nearly all ionic compounds are crystalline solids at room temperature. They generally have high melting points. The total positive charge of an ionic compound is balanced by the total negative charge; thus ionic compounds are neutral. 7) Ionic solids consist of positive and negative ions packed in orderly arrangement. The coordination number of an ion indicates the number of ions of opposite charge that surround the ion in a crystal. 8) When melted or in aqueous solution, ionic compounds can conduct electricity because the ions can move freely when a voltage is applies. 9) Metals are like ionic compounds in some ways. They consist of positive metal ions packed together and surrounded by a sea of electrons. This 4

5 the elements cause gradual changes in both the physical and chemical properties of the elements within a group and within a period. 14) Atomic radii generally decrease as you move from left to right in a given period because there is an increase in the nuclear change while the number of inner electrons, and hence the shielding effect, remains constant. 15) Ionization energy, the energy required to remove an electron from an atom, generally increases as you move from left to right across a period. Ionization energy decreases as you move down a group. 16) Atomic radii generally increase within a given group because the outer electrons are farther from the nucleus as you go down the group. 17) Ionic radii decrease for cat ions and anions as you move from left to right across a period and increase as you move down a group. 18) Electronegativity measures the ability of a bonded atom to attract electrons to itself. It generally increases as you move from left to right across a period. It decreases as you move down a group. arrangement constitutes the metallic bond. 10) The valence electrons in metals are mobile and can travel from one end of a piece of metal to the other. This electron mobility accounts for the excellent electrical conductivity of metals and helps explain why metals are malleable and ductile. 11) Metals are among the simplest crystalline solids. 12) Atoms form covalent bonds when they share electrons. 13) A shared pair of valence electrons constitutes a single covalent bond. Sometimes two or three pairs of electrons may be shared to give double or triple covalent bonds. 14) Sometimes one atom may contribute both bonding electrons in a covalent bond. This type of bond is called a coordinate covalent bond. 15) Resonance structures help visualize the bonding in molecules when more than one electron dot formula can be written. 16) The valence-shell-electron-pair repulsion, or VSPER, theory of molecular geometry states that, as a general rule, molecules adjust their three-dimensional shapes so the valence-electron pairs are as far apart as possible. 17) When covalent bonds join like atoms, the bonding electrons are shared equally and the bond is nonpolar. When the atoms in a bond have different electronegativities, the bonding electrons are shared unequally and the bond is polar. 18) Hydrogen bonds are attractive forces in which a hydrogen covalently bonded to a very electronegative atom is also weakly bonded to an unshared electron pair of another electronegative atom. Hydrogen bonds are strong relative to other dipole interactions. 19) Weak intermolecular forces determine whether a covalent compound will be a solid, liquid, or gas. Weak intermolecular forces determine whether a covalent compound will be a solid, liquid, or gas. 20) Weak attractions between molecules are called van der Waals forces and include dispersion forces, dipole interactions, and hydrogen bonds. 5

6 Essential Facts Processes and Skills Language of Instruction Formative Assessment (for learning) 1) Discuss the processes of radioactivity and radioactive decay. 2) Characterize alpha, beta, and gamma radiation. 3) Use half-life information to determine the amount of a radioisotope remaining at a given time. 4) Compare nuclear fusion and fission. 5) Explain the issues involved in storage, containment, and disposal of nuclear waste. 6) List some applications of radioisotopes in research and medicine. Alpha Particle, Beta Particle, Fission, Fusion, Gamma Radiation, Half-Life, Positron, Radiation, Radioactive Decay, Radioactivity, Radioisotope, Transmutation, Transuranium Elements. 1) Summarize the development of the atomic theory. 2) Explain the significance of quantized energies of electrons as they relate to the quantum mechanical model of the atom. 3) Apply the Aufbau Principle, the Pauli Exclusion Principle, and Hund s Rule in writing the electron configuration of elements. 4) Explain why the electron configurations for some elements are exceptions. 5) Relate the wavelength, frequency, and energy of light. 6) Explain the origin of the atomic emission spectrum of an element. 7) Explain why you can infer the properties of an element based on those of other elements in the periodic table. 8) Use electron configurations to classify elements as noble gases, representative elements, transition metals, or inner transition metals. 9) Interpret group trends in atomic radii, ionic radii, ionization energies, and electronegativities. Amplitude, Atomic Emission Spectrum, Atomic Orbital, Atomic Radius, Aufbau Principle, Electromagnetic Radiation, Electron Configuration, Energy Level, Frequency, Ground State, Hertz, Hund s Rule, Ionic Size, Ionization Energy, Lewis Dot Notation, Metallic Strength, Orbital Notation, Pauli Exclusion Principle, Photon, Quantum Mechanical Model, Spectrum, Wavelength. Electron Configuration Quiz 1) List the characteristics of an ionic bond. 2) Use the characteristics of ionic compounds to explain the electrical conductivity of ionic compounds when melted and when in aqueous solutions. 3) Use the theory of metallic bonds to explain the physical properties of metals. 4) Describe the arrangements of atoms in some common metallic crystal structures. 5) Use electron dot structures to show the formation of single, double, and triple covalent bonds. 6) Use VSEPR theory to predict the shapes of simple covalently bonded molecules. 7) Use electronegativity values to classify a bond as nonpolar covalent, polar covalent, or ionic. 8) Name and describe the weak attractive forces that hold groups of molecules together. Alloys, Bent Molecule, Bonding Pair, Coordinate Covalent Bond, Covalent Bond, Crystal Lattice, Dipole, Double Bond, Hydrogen Bonding, Intermolecular Forces, Intramolecular Forces, Ionic Bond, Linear Molecule, London Dispersion Forces, Lone Pair, Metallic Bonding, Network Solid, Nonpolar Covalent Bond, Octet Rule, Polar Covalent Bond, Polarity, Shared Pair, Tetrahedral Molecule, Trigonal Planar Molecule, Trigonal Pyramidal Molecule, Triple Bond, Unshared Pair, van der Waals Forces, Valence Electrons, VSEPR Theory. Molecule Shapes/Bonding Stated Question or Quiz WebAssign WebAssign WebAssign 6

7 Summative Assessment (of learning) Other Resources Nuclear Half-Life Lab (if time) 100 Reproducible Activities: Chemistry by Instructional Fair, Inc (workbook) p. 34, 35 Planetarium Spectroscope Lab Flame Test Emission Spectra Lab Manipulative Model of the Atom (s and p orbitals) 100 Reproducible Activities: Chemistry by Instructional Fair, Inc (workbook) p. 29,30,31,32,33,36,37 Molecular Shapes Lab Solids Dry Lab 100 Reproducible Activities: Chemistry by Instructional Fair, Inc (workbook) p. 38,39,40,41,42, Reproducible Activities: Physical Science by Instructional Fair, Inc (workbook) p. 47 Textbook Correlation Chapter 28 Chapters 13, 14 Chapters 15,16 Challenge/Extension Link to Physics, p. 844 Link to Astronomy, p. 376 Link to Archaeology, p. 847 Link to Music, p.405 Other Curricular Connection (ELA, Math, S.S., Technology) Chemistry Serving the Environment, p. 862 Chemistry in Careers (Nuclear Physician), p. 881 Chemistry Serving Society, p. 384 Chemistry Serving Industry, p. 407 Chemistry in Careers (Laser Technician and Solid State Chemist), p. 874 Link to Food Science, p. 418 Link to Geography, p. 453 Link to Computer Science, p. 464 Chemistry Serving the Consumer, p. 430 Chemistry Serving Society, p. 468 Chemistry in Careers (Wastewater Engineer), p. 875 Chemistry in Careers (Oncologist), p