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UNIT 5A OBJECTIVES -- ATOMS and the PERIODIC TABLE At the conclusion of this unit, students will be able to: Describe the historical progression of the atomic theory (AT). Explain that science exists in a historical context. Relate the development of the AT to its historical context. Describe individuals and their contributions to the AT. Describe the various models of the atom. Describe the particles that make up atoms. Describe similarities and differences of isotopes. Determine atomic #, mass #, and particles in assigned isotopes. Determine names and symbols of isotopes. Determine average atomic mass of an element. Explain relative abundances of isotopes. Define orbital. Describe shapes and sizes of various orbitals. Identify the valence electrons for a given atom. State the octet rule. Define ion. Describe how ions are formed. Draw electron dot diagrams. PHYSICAL SCIENCE – ATOMS AND THE PERIODIC TABLE 1. Indicate the chemical symbol for each of the following elements: oxygen ______ fluorine ______ iron ______ silicon ______ tungsten ______ tin ______ 2. Indicate which element is represented by each symbol: Ne _________________ P ____________________ Ca __________________ Hg _________________ Pt ____________________ C __________________ 3. The idea that matter is made of tiny particles called "atoms" was first proposed by the Greek philosopher _________________________. 4. The Greek word "atomos" can be translated as _______________________. 5. Atoms are composed of: _____________________, ____________________, and _________________. 5B. Of these, which one determines the chemical behavior of a given atom? _____________________ 5C. The chemistry of an atom is determined by its ___________________________. EXPLAIN WHY: 6. Complete the table of subatomic particles: MASS RELATIVE NAME SYMBOLS CHARGE WHERE FOUND NUMBER MASS (amu) 6A. Of these, which one ABSOLUTELY determines which element an atom is? _____________________ 6B. Define ATOMIC NUMBER: 7. The atomic number of an atom (element) is the number of ___________. 8. For any neutral atom, the numbers of ___________ and ____________ are equal. 9. The ___________ determine the chemical behavior of an atom (element). 10. More specifically, the ______________ electrons determine the chemistry of an atom. 11. Describe what is meant by a "scientific model:" 12. In __________, Rutherford discovered that almost all of the atom’s mass, and all of its positive charge, is concentrated in the center, which he named the __________________. 13. In other words, most of the atom is _________________________________________________. 14. If an atom were the size of Three Rivers Stadium, its nucleus would be the size of a _____________. 15. Describe Bohr’s model of the atom (also known as the _________________________ model): 16. The best model of the atom is referred to as the electron _______ or ______________ model of the atom. 17. Can we describe the motion of the electron in the atom? _____ Instead, we can only refer to the __________________ of finding the electron at any given location. 18. Your text suggests visualizing the electron cloud as similar to _______________. A better suggestion is to think of the electrons as bees located around a central beehive (the nucleus). 19. Can electrons in atoms have "any old" energy, or must they be at specific energy levels? ______________________ 20. The lowest energy that a particular electron can be at is called its ________________ state. 21. Higher electron energy levels are referred to as ____________ states. 22. When an electron "moves" from a higher to a lower energy level it releases its excess energy as a ______________ of ______________________ radiation. 23. _________________ is the identification of substances by the specific energies of electromagnetic radiation that are absorbed or given off. PHYSICAL SCIENCE – ATOMS AND THE PERIODIC TABLE Pages 3 and 4 1. Examine the visual on page 108. Can you come up with a formula to predict the maximum number of electrons that can exist on any given energy level? 2. Use your formula to predict how many electrons can exist on the 5th (____ electrons) and 6th (____ electrons) energy levels. 3. Again, look at the visual on 108, and compare to the p orbital on 109. The picture on 108 looks like a fuzzy version of Bohr’s old __________________ model of the atom, with atoms limited to particular distances from the nucleus. Is that even possible, given the shape of a p orbital? _______ Explain: 4. Define orbital: 5. Our modern model of the atom goes by many names: Electron _________________ model Electron _________________ model ______________________ distribution model ______________________ mechanical model 6. Describe the shapes of each kind of orbital: s: p: d: f: 7. Each individual orbital can hold a maximum of ____ electrons. 8. A given orbital has a name such as 2px. Indicate what each piece of the name tells us: Number (s. a. 2 in 2px) Letter (s. a. p in 2px) Subscript (s. a. x in 2px) 1. For now, skip pages 111-115, except for giving the main idea of these 2 sections: pp. 111-114: _____________________________ p. 115: _____________________________ Now read and take notes on pages116-119. 2. Define ATOMIC NUMBER: 3. Complete the following: The atomic number of carbon is ______. All atoms of iron contain _______ protons. Atoms of ___________________ contain 92 protons. 4. Define MASS NUMBER: 5. Imagine an atom composed of 15 protons, 15 electrons, and 16 neutrons. Complete the following: atomic number: ________ mass number: ________ Identify this atom: __________________________________ Symbol: ____________ 6. Now, imagine an atom composed of 15 protons, 15 electrons, and 17 neutrons. Complete the following: atomic number: ________ mass number: ________ Identify this atom: __________________________________ Symbol: _____________ 7. 31P and 32P are two ______________________ of phosphorous. 8. Name the atom (isotope) that contains 20 protons, 20 electrons, and 22 neutrons: Name: __________________________________ Symbol: _____________ 9. Name the atom (isotope) that contains 47 protons, 47 electrons, and 52 neutrons: Name: __________________________________ Symbol: _____________ 10. Define: ISOTOPE: PHYSICAL SCIENCE – ATOMS AND THE PERIODIC TABLE Pages 5 and 6 1. Isotopes are named by their element name and mass number, such as boron-11 (11B), sodium-23 (23Na), and copper- 63 (______). 2. Cobalt-60 (60Co) is often used for radiation therapy. Atoms of this isotope are composed of ___ protons, ___ electrons, and __ neutrons. 3. The substance __________________ is often used for nuclear weapons. Atoms of this isotope are composed of 94 protons, ___ electrons, and 145 neutrons. 4. A particular isotope of copper is called Copper-63 (63Cu). Atoms of this isotope contain ___ protons, ___ electrons, and ___ neutrons. 5. Complete the chart of isotopes: Name symbol atomic # mass # # protons # electrons # neutrons Sulfur-35 Lithium-7 31 P 22 24 122 52 238 U 17 21 212 Po 42 55 6. Atoms of the isotope 64Ga contain ____ electrons, ___ protons, and ___ neutrons. This isotope has a mass number of ____ and an atomic number of ____. 7. How can the number of neutrons in a particular atom be computed? QUICK REVIEW: 8. Electrons have a charge of ______, a mass of ______, and are found ____________ the nucleus. 9. Protons have a charge of _______ and a mass of _____, and are found ____________ the nucleus. 10. Neutrons have a charge of _____ and a mass of ______, and are found ____________ the nucleus. 11. The chemistry of an atom is determined by its ___________. 12. Carbon occurs in nature as a mixture of two isotopes: carbon-12 and carbon-13. (For now, we will ignore the small amount of carbon-14 that is also present). A. How are atoms of these isotopes the same? B. How are atoms of these isotopes different? 13. Oxygen occurs in nature as a mix of two isotopes: 16O and 17O. Look at the periodic table -- the average atomic mass of oxygen is __________. Which isotope of oxygen do you think is: less than 1% of naturally occuring oxygen? ______________ more than 99% of naturally occuring oxygen? ______________ 14. Neon occurs in nature as a mixture of two isotopes: neon-20 and neon-22. A. For a mix of 50% neon-20 and 50% neon-22 the "average atomic mass" would be _______. For a mix of 1% neon-20 and 99% neon-22 the "average atomic mass" would be (approximately) _____. B. Look at the periodic table. The average atomic mass of neon is __________. What does this tell you about the ratio of neon-20 and neon-22 present in naturally occuring neon? 15. Define: AVERAGE ATOMIC MASS: PHYSICAL SCIENCE – ATOMS AND THE PERIODIC TABLE Pages 7 and 8 USE COMPLETE SENTENCES TO ANSWER THE FOLLOWING ITEMS (Unless asked to list, show, or calculate.) 1. How many outer electrons do atoms of each of the following have? Neon ___ chlorine ____ sodium _____ oxygen _____ 2. Show electron dot structures for the following atoms: C Si Na K O S Ne 3. Explain what determines the chemical behavior of atoms: 4. Explain why we would expect atoms of F, Br, Cl, and I to behave similarly: 5. How (what) did Mendeleev contribute to the modern periodic table? 6. How (what) did Moseley contribute to the modern periodic table? 7. State the Periodic Law: 8. Define "Periodic Table." 9. Define (and match up) the following terms: period, row, column, group, family. A. B. 10. List the noble gases: ______________________________________________ 11. Why are they called the noble gases? 12. These noble gases are also called the _________ or _________ gases. 13. What chemical trait do the noble gases share? Why do the noble gases have such similar chemical behavior? Explain. 14. _________________ determine the chemical behavior of atoms. 15. Show the electron dot structures of the following atoms: F P Li Ca N I O 16. The chemistry of atoms is determined by their _________________, more specifically, it is determined by their ___________ electrons. PHYSICAL SCIENCE – ATOMS AND THE PERIODIC TABLE Pages 9 and 10 For each of the following periodic tables, complete the task assigned. 1. Draw the line separating the metals and nonmetals. Using three colors, color metals, nonmetals, and metalloids. Create a key. 2. Using various colors, color the alkali metals, alkaline earth metals, halogens, and noble gases. Create a key. 3. Using various colors, color the alkali metals, alkaline earth metals, transition metals, inner transition metals,and “other metals.” Create a key. 4. Suggest three questions for the upcoming test: A. B. C. Isotope Mass (u) Half-life Mode of decay Nuclear spin 52 Fe 51.94812 8.28 h EC to 52Mn 0 53 Fe 52.945312 8.51 m EC to 53Mn 7 /2 55 Fe 54.938298 2.73 y EC to 55Mn 3 /2 59 Fe 58.934880 44.51 d β- to 59Co 3 /2 60 Fe 59.934077 1.5 x 106 y β- to 60Co 0 61 Fe 60.93675 6.0 m β- to 61Co 62 Fe 61.93677 68 s β- to 62Co 0 Isotope Mass (u) Half-life Mode of decay Nuclear spin 120 I 119.91005 1.35 h EC to 120Te 2 121 I 120.90737 2.12 h EC to 121Te 5 /2 122 I 121.90760 3.6 m EC to 122Te 1 123 I 122.905605 13.2 h EC to 123Te 5 /2 124 I 123.906211 4.18 d EC to 124Te 2 125 I 124.904624 59.4 d EC to 125Te 5 /2 126 I 125.905619 13.0 d EC to 126Te; β- to 126 Xe 2 128 I 127.905805 25.0 m EC to 128Te; β- to 128 Xe 1 129 I 128.904988 1.7 x 107 y β- to 129Xe 7 /2 130 I 129.906674 12.36 h β- to 130Xe 5 131 I 130.906125 8.040 d β- to 131Xe 7 /2 132 I 131.90800 2.28 h β- to 132Xe 4 133 I 132.90781 20.8 h β- to 133Xe 7 /2 134 I 133.9099 52.6 m β- to 134Xe 4 135 I 134.91005 6.57 h β- to 135Xe 7 /2 Isotope Mass (u) Half-life Mode of decay Nuclear spin 41 Ca 40.9622783 102000 y EC to 41K 7 /2 45 Ca 44.956186 162.7 d β- to 45Sc 7 /2 47 Ca 46.954546 4.536 d β- to 47Sc 7 /2 49 Ca 48.955673 8.72 m β- to 49Sc 3 /2 50 Ca 49.95752 14 s β- to 50Sc 0 51 Ca 50.9615 10 s β- to 51Sc; β- + n to 50 Sc 3 /2 52 Ca 51.9651 4.6 s β- to 52Sc Isotope Atomic mass (ma/u) Natural abundance (atom %) Nuclear spin (I) 54 Fe 53.9396127 (15) 5.845 (35) 0 56 Fe 55.9349393 (16) 91.754 (36) 0 57 1 Fe 56.9353958 (16) 2.119 (10) /2 58 Fe 57.9332773 (16) 0.282 (4) 0 http://www.webelements.com/iron/isotopes.html "A new, improved version of the periodic table" NAME________________ Read the article and answer the following questions: 1. Which American scientist created several of the trans-uranium elements? ____________________ 2. How was this scientist honored in 1951?_____________________ 3. How is this same scientist now being honored? 4. Explain how a cyclotron ("collider", "accelerator") is used to produce new elements: 5. Three groups claimed credit for discovering new elements. Which two organizations resolved the disputes? _______________________________________________________________________ _______________________________________________________________________ 6. According to the article, what determines the chemical behavior of an element? 7. If an atom of potassium-40 was smashed into a "target" atom of uranium-238, what atom would result? potassium-40 plus uranium-238 yields _______________ ___ p+, ___ no + ____ p+, ____ no -----> _______________ 40K + 238U ----> __________ 8. Assume you are working as a scientist at an accelerator, and successfully strike plutonium-239 target atoms with calcium-42 atoms. Here, show the equations (as above in #7) for this process: 9. From #8. REMEMBER -- YOU DISCOVERED IT!! Write a 100-200 word press release for the newspaper, describing what you did and what you discovered. CONSIDER: 1. Write so non-science readers understand. 2. You get to name it! FILL IN THE BLANKS (25 points) Western civilization traces its roots to _________. The __________ empire "took over from" or "built on" the Greek empire and peaked around the year __________. The __________ Ages began after this empire collapsed and lasted from approximately 450 AD to approximately _____________. Then began that great age known as the Renaissance (which means ____________), when people began to ________ for themselves. In approximately 400 BC ______________ stated the first atomic theory. For almost 2200 years there was not an atomic theory because _____________ had disagreed with the idea of atoms. Finally, around the year 1800, ______________ brought back the atomic theory. This time, the theory was based on experimental ________________. The ideas included in this theory were that: "All matter is composed of ____________."; "Atoms of the same element are the ________ and atoms of different elements are _______________."; "Atoms are rearranged in chemical _______________."; and "Atoms can be combined in small whole number ratios to form ___________." Then, in the 1890's, ____________ discovered and described the electron, which is smaller than an atom, and is part of every atom. Thomson was working with a special tool called ________________________. Two modern uses of CRT's include _____________________ and _____________________. Thomson's model of the atom is also referred to as the __________________ model of the atom. Millikan built on Thomson's work and discovered the ____________ and _____________ of the electron. Using gold foil, ________________ determined that most of the mass and positive charge of the atom are concentrated in the central ________. ESSAY: We talked in class about HOW people thought and answered questions, and compared the Middle Ages and the Rennaissance. As a student here at Hempfield, are you more of a “Middle Ages Thinker” or more of a “Renaissance Thinker”? EXPLAIN, providing at least two specific examples from YOUR WORK to convince me of your answer.
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