Introduction to Atomic Models:

1. Introduction to Atomic Models: Diagramming the Atom http://education.jlab.org/qa/atom_model_04.gif

2. Advantages of the Atomic Diagram: • 2 Dimensional – can easily show on a piece of paper • Electron energy levels can be shown with rings – closer to nucleus means lower energy electrons • Conventionally (traditionally) used – so understood worldwide • Easily identifies an atom by clearly showing protons, neutrons & electrons

3. Disadvantages of the Atomic Diagram: Truth: Electrons move around in space, but not along a specific path! • Not 3 Dimensional – can’t easily understand the space used • Rings for electrons can lead to the misconception that electrons have an orbital path • Nucleus appears to take up more space than it actually does Truth: Nucleus is less than 1% of total volume of an atom!

4. Guidelines for Diagramming Atoms: • Before beginning: Determine the number of protons, neutrons, and electrons that are found in that atom. http://lifesciencereality.files.wordpress.com/2008/06/atom.jpg

5. 2. “Rules” about electron energy levels: • Lowest electron energy level is closest to the nucleus. • Electron energy level increases moving away from the nucleus. • Electron energy levels can only hold a certain number of electrons. • Sometimes, electron energy levels can overlap. • Electron energy levels fill up starting with the lowest energy level first.