Intramolecular forces

I'm moving on from the gas laws to intramolecular forces that hold atoms or ions together in a chemical bond.  

This page contains a nice chart with an overview of ionic, covalent and metallic bonds:

http://www.ausetute.com.au/intrafor.html

Here is very quick lecture:

The electronegativity value is the tendency of the atom is attract electrons toward itself. 

Nonmetals attract atoms to form a stable outer electron energy level (or shell) -- nonmetals have high electronegativity values.  A good focal point is the nonmetal fluorine (F) at the top of the halogens  (Group 17) with an electronegativity value of 4.0, the highest value on the Periodic Table.

On the other side of the spectrum is Francium (Fr) at the bottom of the alkali metals (Group 1)  with the lowest electronegativity value of 0.7.

Here's one electronegativity table:

The electronegativity values are in Table S of the New York State Reference Table for the Physical Setting / Chemistry  -- one can be located at http://www.kentchemistry.com/newRT.pdf .

Here's a video that's longer (20 minutes) that focuses on metallic bonding.  It does talk about the Periodic Table, valence electrons, and alloys. 

It's your choice if you want to use this an an introductory video or as a review before testing -- or at the end of the year before final exams.

I had various electrical conductivity testers available to me over the years and testing the electrical conductivity of various substances is a fun lab.  I try to avoid labs requiring specialized materials, but seeing if there are conductivity testers in your department is worth checking out.

If you're handy, perhaps you can make some:

http://www.exo.net/~emuller/activities/chemistry_summer_2007/Conductivity%20tester.pdf

I don't know if I can make this -- I'll let you know if I can!

Here's a simple lab that tests various substances for properties related to metals / nonmetals / metalloids:

http://phs.prs.k12.nj.us/clee/LabMetalNonmetal.pdf

If you need to use different substances, simply change the chart.

Here's a lab that includes directions for making a conductivity tester. 

http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=115&ved=0CEAQFjAEOG4&url=http%3A%2F%2Fwww.waynecountyschools.org%2Fcms%2Flib6%2FNC01000512%2FCentricity%2FDomain%2F3202%2FProperties%2520of%2520Ionic%2520and%2520Covalent%2520Compounds.doc&ei=3zj6Ur3wK8GyyAGRuYAI&usg=AFQjCNF1iiMdsv0pLBDhrR-A5LaAyXBzzg&sig2=tmalAgpcZXHXDZjKGtjzag

And here's a brief video presentation by a student:

She's not wearing lab goggles -- remember, err on the side of caution and wear your goggles!

Go to amazon.com to check out my lab book "Chemistry on a Budget" :
http://www.amazon.com/Chemistry-Budget-Marjorie-R-Heesemann/dp/0578129159/ref=sr_1_1?s=books&ie=UTF8&qid=1389410170&sr=1-1&keywords=chemistry+on+a+budget

Each lab is presented with two possible report formats -- both with the same procedure -- one with 10 questions to be answered as a conclusion, the other with a full laboratory report required.  This was to give the teacher the option of what type of report is desired!

*I'd love to hear from you about your lab experiences, your questions or if you have ideas for other topics for this blog. 

I'm probably moving into a Periodic Table focus and then to chemical bonding, but if you have any requests, let me know!

Have a good rest of the week!