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Name __________________________________________ Topic 2-A Outline Topic 2–A Outline / wksht (AP Chapter 2 Sections 1-5) Questions: The Atom and Periodic table intro. For each section View PPT or Read text section then create the outline. Include: Main concepts and supporting ideas, Examples – conceptual and math problems Two theories of matter: Continuous – Vs. Discontinuous – Democritus 2.1 Atomic theory Theory def. – Dalton ultimate particle model – Postulates: Evidence for – Law of multiple proportions – Examples: Try one: Water is always 11.1% hydrogen and 88.9% oxygen (by weight) Hydrogen peroxide is 5.89% hydrogen, and 94.1% oxygen Show mathematically, how these two compounds illustrate the law of multiple proportions: 2.2 discovery of atomic structure Electrons – CRT Properties of electrons Mass of electron – Millikan’s oil drop exp. Thomson Plum pudding model- Radioactivity Key particles and properties: Nucleus Discovery – gold foil experiment: Rutherford model of the atom – Other subatomic particles ProtonNeutronCYU 1. Which model of the atom was the simplest? What were its characteristics? 2. How did Thomson surmise that electrons were subatomic particles? How did he know they were negatively charged? 3. Why did most of the alpha particles pass through the gold foil undeflected? Why did a few get deflected? 4. Why can’t two atoms pass through one another if there’s so much empty space? Regents questions HDYK (“how do you know”) 2.3 Modern atomic structure Charge cloud model – Subatomic particles: Protons neutrons electrons AMU’s- Atomic number, mass number, and isotopes Atomic number Mass number – Isotope – DYU? How many protons, neutrons, and electrons are in 14C6 ? How many protons, neutrons, and electrons are in 11C6 ? CYU: An atom has 14 protons and 20 neutrons. A. Its atomic number is 1) 14 2) 16 3) 34 B. Its mass number is 1) 14 2) 16 3) 34 C. The element is 1) Si 2) Ca 3) Se D. Another isotope of this element is 1) 34 X 2) 34 X 3) 36 X 16 14 14 Four basic forces in matter: 2.4 atomic weights Examples: Calculating – Mass spectrometer Regents questions: 2.5 Periodic Table (Mendeleev) Periodic law: Groups - Periods - Two types of elements: Table of characteristics Metals Nonmetals Metalloids Noble gases Learning Check: 1. State the modern periodic law: “Properties of elements are…. 2. What are “groups” on the periodic table? How are the members related to one another? 3. What are the periods on the periodic table? how do the properties change across a period? 4. What are the 3 + 1 types of elements? Where is each located on the table? Groups of elements: Group 1 Group 2 Transitional elements Metalloids How do their properties differ? Group 13-16 Group 17 Group 18 LC: 1. What families of elements are so reactive that they are only found in nature combined in compounds? 2. Where are the transitional elements located? What kind of elements are they? Other traits? 3. Which groups on the table contain both metals and nonmetals? Explain 4. Which halogen is most reactive? What trend occurs in melting and boiling points for elements in group 17? Why does this trend occur? 5. List the 7 semimetals (metalloids): Why are they named as such? 6. What elements exist as diatomic molecules when in their pure, uncombined state? Regents Questions HDYK Name __________________________________________ Topic 2-A Questions: 2.1 Atomic Theory 1. In terms of atoms, and in your own words describe the main ideas of Dalton’s atomic theory, relative to …composition of matter…how elements differ…how compounds are formedand …what happens in a reaction2. How does Dalton’s atomic theory account for the law of conservation of mass? 3. How does Dalton’s atomic theory account for the fact that when 1.000 g of water is decomposed into its elements, 0.111g of hydrogen and 0.889 g of oxygen are obtained regardless of the source of the water? 4. A chemist finds that 30.32 g of nitrogen will react with 17.60 g, 35.20 g, 70.40 g, or 88.00 g of oxygen to form four different compounds. (a) Calculate the mass of oxygen per gram of nitrogen in each compound. (b) How do the numbers in part (a) support Dalton’s atomic theory? 2.2 discovery of atomic structure 5. At the time, the hydrogen atom was the smallest particle known. Why did Thomson conclude that electrons were sub-atomic particles? AP 6. Millikan determined the charge on the electron by studying the static charges on oil drops fallilng in an electric field. A student carried out this experiment using several oild drops for her measurements and calculated the charges on the drops. She obtained the following data: (a) What is the significance of the fact that the droplets carried different charges? (b) What conclusions can the student draw from these data regarding the charge of the electron? (c) What value (and to how many significant figures) should she report for the electronic charge? 7. Describe Thomson’s plum pudding model - 8. How did Rutherford interpret the following observations made during the α-particle scattering experiments? a. Most α particles were not appreciably deflected as they passed through the gold foil. b. A few α particles were deflected at very large angles. c. What differences would you expect if beryllium foil were used instead of gold foil in the α-particle scattering experiment? 9. A charged particle is caused to move between two electrically charged plates, as shown here: a. Why does the path of the charged particle bend? b. What is the sign of the electrical charge on the particle? c. As the charge on the plate is increased, would you expect the bending to increase, decrease or remain the same? d. As the mass of the particle increased while the speed of the particle remains the same, would you expect the bending to increase , decrease or remain the same? [section 2.2] 2.3 Modern view of atomic structure 10. Describe the basic structure of the atom according to the charge cloud model of the atom 11. Fill in the gaps in the table, assuming each column represents a neutral atom. Symbol e. 52 Cr Protons 25 Neutrons 30 Electrons 82 64 48 Mass number 86 222 12. What is the “net” charge of the nucleus of any atom? Why? 13. Each of the following isotopes is used in medicine. Indicate the number of protons, and neutrons in each; (a) Phosphorous-32, (b) chromium-51, (c) cobalt-60, (d) technetium-99, (e) iodine-131, (f) thalium-201. 2.3 atomic weights 14. The atomic masses of elements are generally not whole numbers. Explain why. 207 15. Only two isotopes of copper occur naturally, Cu-63 (atomic mass = 62.9296; abundance 69.17%) and Cu-65 (atomic mass = 64.9278; abundance 30.83%). Calculate the atomic weight of copper. 16. Boron has two isotopes: B-10 and B-11. Which is more abundant, given that the atomic mass of boron is 10.81? How do you know? 17. Calculate the atomic mass of bromine. The two isotopes of bromine have atomic masses and relative abundance of 78.92 amu (50.69%) and 80.92 amu (49.31%). 2.4 Periodic table 18. Why did Mendeleev leave blank spaces in his table? 19.Name two elements that have properties similar to those of the element Strontium. How do you know? 20. What is periodic about the periodic table? 21. State the modern periodic law: 22. What are the common properties of metals? …of nonmetals? 23. Give the name and symbol of each: a. any nonmetal in group 14 (4a) b. a diatomic element in period 1 c. the halogen in period 3 d. the first alkaline earth metal e. a member of group 1 which is not an alkali metal 24. The explosion of an atomic bomb releases many radioactive isotopes including strontium -90. Considering the location of strontium in the periodic table, suggest a reason for the fact that this isotope is particularly harmful to humans. AP 25. The attractive force between charged particles is represented by coulombs law: Force = kQ1Q2 where Q1 and Q2 are the respective charges of the two particles, d= the distance between the d2 particles, and k is a proportionality constant determined the units of Q and d. Calculate the force on an electron (Q = -1.6 x10-19 Coulombs) , exerted by a single proton if the two particles are 0.53 x 10-10 m apart. The constant k in coulomb’s law is 9.0 x 10 9 N•m2/C2 (N = Newton, the SI unit of force)