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Chemistry Unit Objectives 2.1a Recognize that the Periodic Table is organized by atomic number and electron levels (horizontally into series/periods and vertically into families/groups), and explain why elements in the same family/group of the Periodic Table have similar properties. Use the Periodic Table to determine the atomic number and atomic mass of common elements. -Use the periodic table to get information about an element (isotope) including the element’s atomic number, mass number, number of neutrons in an isotope and the number of valence electrons. -Describe the general trends of reactivity and mass found in the periodic table in terms of valence electrons. 2.2a Describe that electrons are located in different energy levels in an atom and that the outer electrons determine its chemical properties. - Describe the current model of the atom. -Using information from the periodic table draw a Bohr model of the atom and explain the structure. 2.2b Identify and describe that when two or more atoms chemically combine, they either share electrons (covalent bond, which can be polar or non-polar) or transfer electrons (ionic bond). -Explain how and why atoms form ions and combine in ionic bonds through the transfer of electrons. -Explain how and why atoms form covalent bonds through the sharing of electrons. -Describe the properties of covalent molecules and ionic compounds in terms of the bonding structure. -Describe how electrons are shared in polar and non-polar bonds and explain why they are shared the way they are. 2.3a Use information (e.g., pH, melting point, conductivity, magnetism, and reactivity) to classify, identify, and separate substances. -Explain the difference between chemical and physical changes and give an example of each. -List and describe several chemical and physical properties and processes that can be used to separate substances. 2.4a Explain that a chemical equation shows how atoms are rearranged during a chemical change and translate word equations into chemical equations. 2.4b Determine whether the products and reactants of a chemical equation are balanced in order to show that matter is conserved. 2.5a Identify whether chemical reactions are exothermic or endothermic. 2.6b Explain that in any transfer or transformation of energy, some of the energy is transformed into heat. -Explain the difference between energy transfer and energy transformation and give examples of each. 2.8a Compare the total mass and total energy of all materials before and after a physical or chemical interaction. Vocabulary Terms: matter element energy solution physical change density pH reactivity plasma gas melting condensation conservation of matter neutron nucleus mass number period(series) metal average atomic mass polar bond chemical equation endothermic cation pure substance mixture homogeneous mixture physical property melting point filtration chemical property chemical change solid kinetic theory vaporization sublimation atom electron periodic table isotope group(family) non-metal ionic bonding non-polar bond product exothermic compound heterogeneous mixture molecule conductivity boiling point distillation flammability precipitate liquid phase change freezing deposition proton energy level atomic number valence electron atomic mass unit metalloid covalent bonding chemical equation reactants anion Objective 2.1a -How many protons are in an atom of silver? -What is the average atomic mass of Barium? -What is the mass number of the most common isotope of sulfur? How many neutrons are in this isotope? -How many electrons are in an atom of Xenon? -If a Bromine atom has 55 neutrons, what is the mass number of this isotope? -An atom has a mass number of 112 and has 64 neutrons. What is the element? Explain how you determine this. -Explain the similarities and differences between a molecule, compound, atom, isotope and element. -Explain the order in Mendeleev’s periodic table. -Discuss why/how his periodic table was considered good science. -Identify the location of metals, non-metals and metalloids on the periodic table. -Explain the trends of the period table relating to atomic number, average atomic mass, valence electrons and reactivity. -What do all elements in the same period(row) have in common? -What do all elements in the same group(column) have in common? -Describe the characteristics of the akali metals, the carbon family, the halogens and the noble gases. -How can you distinguish between man-made and naturally occurring elements? -What are the units we use to measure the mass of atoms and how is the unit defined? Objective 2.2a -Draw a Bohr model of the atom for Ne and P. On the model label the following items: nucleus, electron, proton and neutron. List the number of protons, electrons and neutrons(use rounded average atomic mass for mass number) for each of the elements. -What three characteristics can be used to distinguish between the subatomic particles? -Explain the basic ideas of and evidence that supports each of the following theories of the atom: Greek, Dalton, Thomson, Rutherford, Bohr and Modern/Electron Cloud. -Explain how the Bohr model explains the observations from the flame lab. Your answer should include energy levels. -Why does the outer ring of electrons determine the chemical properties of the element? Objective 2.2b -Describe how and why an ionic bond forms. -What types of elements form ionic bonds? Give two examples. -Define anion and cation. What types of elements become anions and what types become cations? -How many valence electrons do the following elements have? When they become ions how many electrons do they gain or lose and what is the charge of the ions? Na Ba O F Cl Al K S Ra -What are the characteristics of an ionic compound? -Explain why ionic compounds are both brittle but also have very high melting points in terms of their bonding. -Explain why ionic compounds conduct electricity when dissolved in water but not when solid. -What types of elements form covalent bonds? Give two examples. -Explain how covalent bonds form and what happens to the electrons. -Describe the characteristics of covalently bonded molecules. -Explain why many covalently bonded molecules exist as gases at room temperature in terms of their bonding. -What is a polar covalent bond? -Explain why polar covalent molecules such as water hold each other more tightly than non-polar covalent molecules like carbon dioxide. Objective 2.3a -Classify the following as physical or chemical properties. Mass Malleability Melting Point Boiling Point Shape Flammability Conductivity Reactivity Color -Classify the following as physical or chemical changes and explain. a. Cooking a turkey b. Painting a wall c. Melting chocolate d. Bending a metal rod e. Mixing oil and water f. Combing two clear liquids and getting a cloudy red liquid g. Combining a clear liquid and grey powder resulting in shower of sparks and smoke -What is happening on the atomic level during a chemical change? -What is happening on the atomic level during a physical change? -How might you separate a mixture of three different liquids with different boiling points? -How might you separate a mixture that contains particles of different sizes? -How might you separate metals from non-metals? Objective 2.4a -What are the pieces of evidence that indicate a chemical reaction took place? -Translate the following sentences into chemical formulas. a) One methane(CH4) molecule reacts with two oxygen molecules (O 2) to produce one molecule of carbon dioxide and two molecules of water. b) One atom of sodium combines with one atom of chloride to make one unit of the compound sodium chloride. c) Two molecules of hydrogen peroxide (H2O2) decompose into two molecules of water and one molecule of oxygen (O2) Objective 2.4b -Identify the reactants and the products in the chemical reactions below and balance the following chemical reactions. 1. 2. 3. 4. 5. 6. 7. SO2 + O2 SO3 P + O2 P4O10 Mg + O2 MgO N2 + H2 NH3 Na + Cl2 NaCl H2 + O 2 H2O H2O2 H2O + O2 -Explain why chemical equations must be balanced. Objective 2.5a -How is chemical energy stored? -Explain the role of energy in an exothermic reaction. How is it transformed and transferred during the reaction? Draw a chemical energy vs. time graph. -Explain the role of energy in an endothermic reaction. How is it transformed and transferred during the reaction? Draw a chemical energy vs. time graph. -Identify the following as an endothermic or exothermic change/reaction. a. Melting Ice b. Freezing a popsicle c. Lighting a match d. Shaking a hand warmer e. Baggie Lab f. TNT Objective 2.6b -What is an energy transfer? -What is an energy transformation? -When two objects, one hot and one cold come into contact with each other they end up with the same temperature. Was energy transferred or transformed? -During a chemical reaction two chemicals are mixed together at room temperature. When they react they produce a new chemical, smoke and flame. Was energy transferred or transformed? -During any transfer or transformation of energy what type of energy is always produced? Objective 2.8a -Explain why chemical equations must be balanced. -Explain how matter is conserved during a chemical change such as burning a match or during a physical change such as melting water or dissolving salt. -Explain how energy is conserved during a chemical change such as burning a match or activating a cold pack.