3 The Atom



  • Understand the definition of atomic mass and atomic number.
  • Differentiate between the location, charge, and mass for an electron, proton, and neutron.
  • Define an ion and determine the protons and electrons present in specific ions.
  • Define isotope and determine the protons, electrons, and neutrons present in an isotope.
  • Determine average atomic mass of an element based on isotopic data.

Academic Standards

C.1.32 Describe the possible subatomic particles within an atom or ion.
  • Identify the location, charge, and mass of protons, neutrons, and electrons.
  • Calculate the number of protons, neutrons and electrons for isotopes.
  • Calculate the average atomic mass from isotopic data.
C.2.3  Explain that John Dalton's modernization of the ancient Greek ideas of element, atom, compound, and molecule strengthened the new chemistry by providing physical explanations for reactions that could be expressed in quantitative terms.

C.2.6  Explain that the application of the laws of quantum mechanics to chemistry by Linus Pauling and others made possible an understanding of chemical reactions on the atomic level.


  1. History of Atomic Theory
  2. Quiz 1:  Matter and Atomic Theory

  3. Atomic Mass and Isotopes
  4. ISTEP
    • Great Discoveries: Chemistry video (hosted by Bill Nye)
    • Element Puns extra credit

  5. Quiz 2:  Atomic Mass and Isotopes

*Note:  Due to the break caused by ISTEP testing, we will do two small quizzes for the chapters on Matter and Atomic Theory instead of one larger test.

Recent Files

  • Atomic Number and Mass Worksheet.pdf   49k - Sep 16, 2008, 9:07 AM by Jeremy Horner (v2)
    ‎Atomic number, mass, and isotopes worksheet from class.‎
  • Element tshirt template.docx   20k - Sep 8, 2008, 7:32 AM by Jeremy Horner (v2)
    ‎Element project poster template. (Note: this is in Microsoft Office 2007 format)‎
  • Element Poster Project.pdf   288k - Sep 5, 2008, 10:42 AM by Jeremy Horner (v2)
    ‎Element Poster project sheet‎
  • Atom History Pictures.pdf   419k - Sep 5, 2008, 10:42 AM by Jeremy Horner (v2)
    ‎Pictures of the scientists (just for fun)!‎
  • Atom History Tables.pdf   178k - Sep 5, 2008, 10:42 AM by Jeremy Horner (v2)
    ‎History of Atomic Theory tables for notes‎
Showing 5 files from page Atom Files.

Recent Announcements

  • Start of Second Semester Welcome back!  Our new unit, Stoichiometry, has a page up now.  Expect more soon!
    Posted Jan 5, 2009, 8:01 AM by Jeremy Horner
  • End of First Semester! I hope finals went well!  With the first semester over I have removed links to the first semester chapters.  If you still need that material for any reason just let ...
    Posted Dec 19, 2008, 7:50 AM by Jeremy Horner
  • Chemical Bonds Review Key Answer key with selected answers has been posted in the files section of Unit 7 Chemical Bonds.  I also have an answer key available in my room.Currently Lewis structures ...
    Posted Nov 24, 2008, 11:38 AM by Jeremy Horner
  • Chemical Bonds Review The review has been posted for Chemical Bonds.  Go to the Files section on Unit 7: Chemical Bonds.The answer key will be posted sometime over the weekend, so stay ...
    Posted Nov 21, 2008, 8:41 AM by Jeremy Horner
  • Chemical Bonds Unit Assignments Most assignments for this chapter are not available as digital copies on the website.  If you need any of the naming worksheets, please drop by my room.  I have extra ...
    Posted Nov 17, 2008, 7:41 AM by Jeremy Horner
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Other Resources

Google The best search engine ever! 
Periodic Videos University of Nottingham element videos (the site I showed in class) 
Printable Periodic Tables Several different versions of the periodic table, including ones with atomic radius, oxidation number, electronegativity, and more! 
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