04+Atomic+Theory

= Objectives= 4.1 Defining the Atom 4.2 Structure of the Nuclear Atom 4.3 Distinguishing Among Atoms
 * How did Democritus describe atoms?
 * How did John Dalton further Democritus's ideas on atoms?
 * What instruments are used to observe individual atoms?
 * What are three kinds of subatomic particles?
 * How can you describe the structure of the nuclear atom?
 * What makes one element different from another?
 * How do you find the number of neutrons in an atom?
 * How do isotopes of an element differ?
 * How do you calculate the atomic mass of an element?
 * Why is a periodic table usueful?

=Outlined Notes= = =

=**Chapter 4.1 Defining the Atom**=

a. an atom is the smallest particle of an element that retains its identy in a chemical reaction. 1. __Democritus' Atomic Philosophy__ b. Greek philosopher Democritus was amoung the first to suggest the existence of atoms. 2. __Dalton's Atomic Theory__ c. the real nature of atoms and the connection between observable changes and events at the atomic level were not established for more than 2000 years after Democritus. A. __Dalton's Atomic Theory__ Section 4.2 Structure of the Nuclear Atom I. //__Subatomic Particles__// 1. J.J. Thompson; English physicist discovered the electron.
 * I. __Early Models of the Atom__**
 * 1) Democritus believed that atoms were invisible and indestructble.**
 * 2) By using experimental methods, Dalton transformed Democritus' ideas on atoms into a scientific theory.**
 * Three kinds of subatomic particles are electrons, protons, and neutrons.**



1a) **__Electron__**- negativly charged subatomic particles 2a) **__Cathode Ray__**- a glowing beam of light.

- a positively chraged plate attracts the cathode ray while the negativly chrarged plate repels it. 2: Robert A. Millikan; U.S. physicist -carried out experiments to find the quality of charge carried by an electron. Milikan

3a) **__Protons__**- positivly charged subatomic particles 4a) **__Neutrons__**- subatomic particles with no charge.

II. __//The Atomic Nucleus//__ 1a) __**Nucleus-**__ the tiny central core of an atom- composed of protons and neutrons.
 * Rutherford's Gold Experiment
 * The Rutherford Atomic Model
 * In the neuclear atom, the protons and neutrons are located in the nuclues. The electrons are distrubited around the nuclues and occupy almost all the volume of the atom.**



1)**Atom Number** 1a)Elements are different because tey contain different numbers of protons. 1b) **__Atomic Number__**- number of protons in the nucleus of an atom of that element 2)**Mass Number** 2a) The number of neutrons is an atom is the difference between the mass number and atomic number. 2b)**__Mass Number__**- Total number of protons and neutrons in an atom 2c) Number of Neutrons=Mass Number-Atomic Number
 * 4.3 Distinguishing Among Atoms**

= =

=Reference Pages=

= Practice Problems=

80% Iodine-127, 17% Iodine-126, 3% Iodine-128
0.80 x 127 = 100 0.17 x 126 = 21 __0.03 x 128 = 3.8__ 100. 21. __+ 3.8__
 * 124.8** *BUT, because of significant figures, the answer is **120**

99% Hydrogen-1, 0.8% Hydrogen-2, 0.2% Hydrogen-3
0.99 x 1 = 0.99 0.008 x 2 = 0.016 __0.002 x 3 = 0.006__ 0.99 0.016 __+0.006__
 * 1.012** *BUT, because of significant figures, the answer is **1.01**

50.0% Gold-197, 50.0% Gold-198
0.50 x 197 = 99.0 __0.50 x 198 = 98.0__ 99.0 __+ 98.0__
 * 198.0** (significant figures are correct)

15% Iron-55, 85% Iron-56
0.15 x 55 = 8.3 __0.85 x 56 = 48__ 8.3 __+ 48__
 * 56.3** *BUT, because of significant figures, the answer is **56**

95% Nitrogen-14, 3% Nitrogen-15, 2% Nitrogen-16
0.95 x 14 = 13 0.03 x 15 = 0.45 __0.02 x 16 = 0.32__ 13 0.45 __+ 0.32__
 * 13.77** *BUT because of significant figures, the answer is **14**

98% Carbon-12, 2% Carbon-14
0.98 x 12 = 12 __0.02 x 14 = 0.28__ 0.28 __+ 12__
 * 12.28** *BUT, because of significant figures, the answer is **12**

Category: [|Chemistry] > [|Physical Chemistry] > [|Atomic structure and spectra] > [|Structure of hydrogenic atoms]Tags: [|Chemistry], [|Physical Chemistry], [|uranium atom], [|Structure of atom] [|login to view the answer] || Medium || Category: [|Chemistry] > [|Physical Chemistry] > [|Atomic structure and spectra] > [|Structure of hydrogenic atoms]Tags: [|Chemistry], [|Physical Chemistry], [|Structure of atom], [|Frequency and wave number] [|login to view the answer] || Medium || Category: [|Chemistry] > [|Physical Chemistry] > [|Atomic structure and spectra] > [|Structure of hydrogenic atoms]Tags: [|Chemistry], [|Physical Chemistry], [|Structure of atom], [|Wavelength and wave number] [|login to view the answer] || Medium || Category: [|Chemistry] > [|Physical Chemistry] > [|Atomic structure and spectra] > [|Structure of hydrogenic atoms]Tags: [|Chemistry], [|Physical Chemistry], [|Structure of atom], [|The energy of photon] [|login to view the answer] || Medium || Category: [|Chemistry] > [|Physical Chemistry] > [|Atomic structure and spectra] > [|Structure of hydrogenic atoms]Tags: [|Chemistry], [|Physical Chemistry], [|photoelectric effect], [|Structure of atom] [|login to view the answer] ||
 * Question || Difficulty ||
 * ==== Physical Chemistry Practice 1 - Chapter 1, Problem 1P ====
 * ==== Physical Chemistry Practice 2 - Chapter 1, Problem 2P ====
 * ==== Physical Chemistry Practice 3 - Chapter 1, Problem 3P ====
 * ==== Physical Chemistry Practice 4 - Chapter 1, Problem 4P ====
 * ==== Physical Chemistry Practice 5 - Chapter 1, Problem 5P ====

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=== =Assignments=

=Labs= [|**http://www.eol.ucar.edu/~beaton/ChemWeb/labs/atomtheorylabs.html**] Isotopes and Atomic Mass Lab [] [] [] Rutherford's Gold Foil experiment

=Sample Test= [] Practice Quiz [] Practice Game [] Atomic Theory Quiz [] Atomic Theory Quiz 2 [] [] Chemistry Pre-Test

= = =Links [] Modern Atomic Theory= [] [|http://web.jjay.cuny.edu/~acarpi/NSC/3-atoms.htmhttp://www.ric.edu/faculty/ptiskus/chemical/http://library.thinkquest.org/27948/bohr.htmlhttp://www.visionlearning.com/library/module_viewer.php?mid=50http://dl.clackamas.edu/ch104-04/dalton's.htm] [|http://www.visionlearning.com/library/module_viewer.php?mid=50] [|__http://www.electricianeducation.com/theory/atomic_theory.htm__] [] [] [] [] [] [] [] [|http://www.chem1.com/acad/webtext/intro/AT.html][|__http://www.visionlearning.com/library/module_viewer.php?mid=50__] http://www.3rd1000.com/chptr3.htm [] [|://library.thinkquest.org/27948/bohr.http://www.iun.edu/~cpanhd/C101webnotes/composition/dalton.html]
 * __ [] __**