Atomic+Theory+Unit



__Chemical Bonding__

Government Outcomes for Structure unit

Activity 1: Developing the Concepts and theories of light and electrons that lead to the development and understanding of Atomic Theory

A) What is electromagnetic energy?

B) Electric Force Fields view some of this for a brief understanding[| electric force fields.]

C) [|Vibrating Charges]

D) Electromagnetic radiation media type="youtube" key="cfXzwh3KadE" width="560" height="315"

Classical Theory Wave interference patterns using water waves can be compared to light. If light is a wave then it should exhibit interference patterns as well. however if light were a particle (as newton thought) what would the pattern look like? media type="youtube" key="fwXQjRBLwsQ" width="560" height="315" But the fact that light was a wave caused difficulty in explaining black box theory and the UV catastrophe. This was solved by Maxwell Planck.

Einstein drew upon Planck's work to explain the photoelectric effect. This won him a Nobel Prize. The photoelectric effect is the energy that is created when light is shined on a highly conductive metal such as sodium. It was originally thought that the electromagnetic waves of light cause the electron particles to oscillate in frequency with the light and move through the solid creating a current. (This is the idea behind solar power). It was expected that the greater the intensity of light (brightness), the more energy that would be created in the metal. An experimental design was created to test the energy (current and speed) that could be created when light is directed onto a metal surface. The speed or energy each electron possess could be measured by creating resistance for the the moving electrons such that in order for them to leave the metal they would need a minimum threshold energy. The resistance could be adjusted, thus a moving electron must posses at least enough energy to overcome the resistance in order to leave the metal. The higher the resistance the more energy or speed the electron had when it was released from the metal. What was found in this experiment was that the increase in light intensity increased the number of electrons moving in the metal but not the energy they carried. A second more startling observation was made when different colours (freqeuncies of light were shone on the metal). check out this demo and describe this startling observation.[|photo electric effect]

Activity 2:  Print Atomic Theory Experimenting with models

media type="custom" key="27826585"

Rutherford Movie media type="youtube" key="XBqHkraf8iE" width="560" height="315"

Activity 3:  These are Scanning electron microscope images. Use the link below to complete the worksheet phytoplankton) || to a pepper seed. ||
 * [[image:coristines-closet/diatom.gif]] || This is a picture of a diatom (a unicellular
 * [[image:coristines-closet/peppercorn.jpg width="504" height="339"]] || This is an image of a crystal of salt compared

(STE:1.1,1.2) How has our understanding of atomic theory enabled us to create technology that we can use to further our understanding of the world around us? How has the knowldege we have gained about atomic theory been used to benefit society?

Scanning [1_5|electron microscope basics]

Activity 4: worksheet A) Theory of [|light spectroscopy] B) examples of [|line spectra] [|bohr and spectroscopy] [|Bohr model using energy level] Debroglie stood classical theory on its head when he considered that if light could act as particles than perhaps Electrons could act as waves? Then shouldn't they result in interference patterns similar to water and light waves? [|electron interference patterns] Now examine the results of Debroglie's concept = standing waves that can only be created by whole numbers [|Hydrogen model]

Review by comparing the various models of the atom [|Atomic models]

**Activity # 5**: Planck developed the relationship between energy and light as E=hf, where h=6.63 x 10-34 (planck's constant). Balmer developed an equation to determine the relationship between frequencies of light in a line spectra E = R (1/ni2 -1/nf2) where R = rydberg's constant =2.18 x 10-18), ni2 = the initial energy level squared, and nf2 = the final energy level squared). Determine the expected colour of light an electron would emit if it underwent a transistion from n2-n3 (the second energy level to the third) If the E's are assumed to be equal.

**Activity #6: Ion configurations** To see a visual of finding the ion [|electron configuration] try this link For more information on Electron [|configurations for ions] as well as a worksheet try this link.

[|Science Simulation Site](the class code is ZWR7ZQ6DC4) You will need to sign yourself in as a new student so follow the procedure given)