Tuesday, May 17, 2011

The Out of this World Octet Rule!

Q: What is the out of this world octet rule?
A: The octet rule states that in forming compounds, atoms tend to achieve the electron configuration of a noble gas (*they do NOT actually become a noble gas*) 

  • an octet is a set of eight. 
  • noble gases except He have eight electrons in its highest energy level. 

a. "atoms of metals tend to lose their valence electrons, leaving a complete octet in the next-lowest energy level. Atoms of some non-metals tend to gain electrons or to share electrons with another nonmetal to achieve a complete octet."

  • recall that a valence electron is an electron in the highest occupied energy level of an atom.
    • s and p orbitals are considered the valence electrons (note: 2 electrons in the s orbitals, and 6 in the p orbitals)
    • Beginning with the n=3 principle quantum number, the d orbitals become available.
b. Exceptions to the octet rule: 
1. Molecules with an odd number of electrons
Ex: There are 5 valence electrons around the nitrogen. A double bond would place 7 around the nitrogen, and a triple bond would place 9 around the nitrogen.
 unable to get an octet around each atom.

2. Molecules in which an atom has less than an octet
Ex: BF3

  • commonly seen between Boron and Beryllium)

3. Molecules in which an atom has more than an octet
  • Third period elements sometimes exceed the octet rule by using their empty d orbitals to accommodate additional electrons

    • Atoms with an empty d-sublevel can expand their octet to 10 or 12 electrons if necessary.
      • Third period elements sometimes exceed the octet rule by using their empty d orbitals to accommodate additional electrons

    Thursday, April 7, 2011

    Nuclear Chemistry

    For this blog I chose to research question number two:
    2)      Nuclear chemistry has found many applications in medicine. Research some of these applications and discuss them to the best of your ability. There are also health risks associated with radiaton  which you could discuss and research. While I do not expect you to understand or explain every detail, do your best to give as much detail as possible.  Be sure to also include specific nuclear reactions involved (among your applicatons, you can also discuss MRI which is often misuderstood as radioactive eventhough it isn't. No nuclear reaction is involved but the nucleus is an essential part of it. In fact, it is referred to something different in a chemistry setting (NMR). Why do you think they changed the name?)

     I decided to  focus specifically on the procedure of nuclear medicine, the applications of nuclear medicine, and the health effects of radiation. 
    *While viewing a glogster remember to scroll through each box. Hope you enjoy!

    Tuesday, February 1, 2011

    Extra Credit Blog!


    Ionic or Covalent?


    Emily H.
    “I have a smaller chance of breaking apart”
    “I would rather be a strong bond than a weak one”
    “I like to share/hang out with my friends”
    “I strongly believe that opposites attract”
    “Because they are the strongest bonds ofcourse!”
    “I prefer sharing rather than transferring”
    It is strong and has a higher melting point therefore is harder to break the bonds
    Emily K.
    “I would rather be a stronger bond so that it would be hard for me to be broken apart, whether I was melted or boiled”
    “I like to share!”
    “I like being the strongest!”
    “I’ll be the “tough guy”
    “I’m all about metal”
    Doesn’t like to share
    “Network solids are the strongest”
    Mrs. Van Buskirk
    “They have the prettiest colors”

    Haiku's about how electrons behave when forming a covalent compound!
     I never transfer
    Covalent bonds I answer
    All I do is share

    Covalent Bonding
    Sharing valence electrons
    To become like gas

    Tuesday, December 14, 2010

    Wednesday, November 10, 2010

    Chemistry Final Exam Review #4



    Tuesday, October 5, 2010


    (Click the link to view research on the Neutron) http://esher.glogster.com/neutron/

    **don't forget to scroll through the text.

    Thursday, September 9, 2010

    Pretty as a Penny

         For this project I chose to use a penny because it is an unique object, but also one that is often seen in ones life. I was also very curious to see what affects certain chemicals had on the penny, therefore I observed some physical properties of a penny and some chemical properties as well. My results were as follows:

    Physical Properties:
    weight: before 1982 a penny weighed 13.1 g and after 1982 it weighed 12.5 g. The reason for this weight difference is because the composition is different between 1982 and present day pennies. Pennies made from 1944-1982 were made out of 95% copper and 5% zinc. Pennies made from 1982-2010 are/were made out 2.5% copper and 97.5% zinc. Thus concluding copper is heavier than zinc.
    volume of 1982-2010 pennies: 360mm3.
    color: copper brown 
    circumference: 19mm
    smell: copper iron smell (alike blood) 
    density: pre 1982: 3.11g post 1982: 2.50g
    diameter: 19mm
    radius: 9.5mm  

    Discovering Chemical Properties through making Chemical Reactions 
    For the first experiment to test the chemical properties of the penny Katherine and I placed a  2010 penny and a penny before 1982  between two layers of the paper towel, which were coated in vinegar. We let the pennies sit between the layers over night. When we checked the pennies in the morning we discovered that a chemical reaction had occurred. The copper reacted with the vinegar creating a green compound called copper acetate on the top of the penny and heavily around the edges. After researching we learned that that the green residue is also on the statue of liberty, except the statue of liberty is copper sulfate. 

    When we soaked the pennies in clorox bleach we discovered that a similar chemical reaction occurred when we soaked the pennies in vinegar. A green residue also formed when they were soaked in bleach. Although we do not have proof that this was also the formation of copper acetate. However, there was less green crust on the outside of the penny when it was soaked in bleach than when it was soaked in vinegar.

    In our third experiment we decided to soak the pennies in water  and leave them over night. Both rusted however, the older penny rusted mores so than the newer one. 

    For the fourth experiment we soaked the pennies in jewelry cleaner which polished both pennies. Who knew that underneath all that dirt the older penny was almost as shiny as the 2010 penny?

    Our last and final experiment is somewhat incomplete. We had heard that if you soaked a penny in coke that eventually the penny would disintegrate and be "eaten" completely by the coke. Fascinated by that we tried it. We discovered that after a day of soaking not much had change. We think that there was a slight change in the size and shape of the penny, but we are unsure if the change was accurate. Katherine and I plan to continue the coke experiment, because we feel that over time it will eventually happen, and we are determined to discover the answer.

    Work Cited: