Attractive Forces part 1

1. Attractive Forces part 1

2. Matter • We have talked about the different states of matter and the differences in the behavior of particles in each state. • What is it that determines the state of matter at room temperature? • How does the nature of attractive forces in a material affect its properties?

3. Forces of Attraction • Particles can be held together by various forces. • These forces fall into different categories depending upon the nature of the attraction. • There are forces that occur within the particles of a substance (within molecules or ionic compounds); these forces are between atoms or ions and tend to be stronger forces.

4. Forces of Attraction • Other forces are attractions between particles of a substance (between separate molecules or between the atoms of atomic substances such as helium or xenon). • These forces between particles tend to be weaker forces than those within the particles of a sample, with the notable exception of the attractions that exist between ions.

5. Strong Forces of Attraction • Strongforces exist continuously in a substance due to sharing or transfer of electrons in a unit of a substance (molecules and ionic compounds). • They vary in strength, depending upon the composition of the substance. • The strength of the bond is indicated by how much energy is required to break the bond.

6. Strong Forces of Attraction

7. Strong Forces of Attraction • It can take from 400-4000 kJ/mol to break the strongest bonds, which result from the transfer of electrons between atoms to form ions. • The nature of the ionic bond:

8. Strong Forces of Attraction • It can take from 150-1100 kJ/mol to break covalent bonds, which indicates they are still very strong. • Covalent bonds arise from sharing electrons:

9. Strong Forces of Attraction • The previous slide indicated equal sharing, but it is also possible to have unequal sharing of electrons in a covalent bond (creating a polar bond).

10. Strong Forces of Attraction • A comparison of substances exhibiting these strong forces of attraction shows the general progression from equal sharing of electrons to complete transfer. ionic and covalent bonding.flv polarity_of_molecules.flv

11. Strong Forces of Attraction • Metallic bonding is a little different, and requires between 75-1000 kJ/mol to break.

12. References: • http://www.chem.purdue.edu/gchelp/liquids/character.html • http://www.chem.wisc.edu/~newtrad/CurrRef/BDGTopic/lab/Crystlab2.GIF • http://lgfl.skoool.co.uk/uploadedImages/coord11.2_covalentbonding2_v2.gif • http://www.dur.ac.uk/p.m.johnson/electric_circuits/images/dia_atom_cores.gif • http://www.chemistry.wustl.edu/~courses/genchem/Tutorials/Water/images/nacl.jpg • http://web.arc.losrios.edu/~borougt/DiamondStructure.jpg • http://www.oocities.org/rjwarren_stm/PolarityOHbond.jpg • http://www4.nau.edu/meteorite/Meteorite/Images/HydrogenBond.jpg • http://cost.georgiasouthern.edu/chemistry/general/molecule/polar.htm • http://virtual.yosemite.cc.ca.us/webbg/chem101/ch11lecture/intermolecforces.htm • http://www.grandinetti.org/resources/Teaching/Chem121/Lectures/BondPolarity/ColvanttoIonic.gif • http://www.drkstreet.com/resources/metallic-bonding-animation.swf • http://www.chem.ufl.edu/~itl/2045/matter/FG11_002.GIF • http://mysite.verizon.net/kdrews47/interactions/ldf.gif • http://www.colorado.edu/physics/2000/applets/h2ob.html • http://antoine.frostburg.edu/chem/senese/101/liquids/faq/h-bonding-vs-london-forces.shtml • http://cost.georgiasouthern.edu/chemistry/general/molecule/forces.htm • http://www.bbc.co.uk/scotland/learning/bitesize/higher/chemistry/images/bonding_fig11.gif • http://www.northland.cc.mn.us/biology/Biology1111/animations/hydrogenbonds.html • http://www.chem.purdue.edu/gchelp/liquids/ioninddp.gif • http://chemwiki.ucdavis.edu/@api/deki/files/3831/=160inducedipole.gif

13. References - Videos: • http://www.youtube.com/watch?v=QqjcCvzWwww • http://www.youtube.com/watch?v=LKAjTE7B2x0&NR=1 • http://www.youtube.com/watch?v=LGwyBeuVjhV • http://www.youtube.com/watch?v=cThvGD-o_90