03/10/09

TODAY'S CLASS:

Ms. K read through the GR 12 CHEMISTRY Atomic Structure: ELECTRON CONFIGURATIONS handout.

Introduced in the handout was electron configuration, being the arrangement of electrons in an atom. Atom's always want to be in their lowest-energy system possible, to remain most stable. The three rules/principles of how orbitals are filled are:

a) The Aufbau principle
- which states that each electron fills the lowest energy orbital available. For example, the aufbau diagram shows how the energy increases from 1s, 2s, 2p,3s,3p and so on.

b) The Pauli exclusion principle
- which states that a maximum of two electrons may occupy an orbital, but only if the electrons have opposite spins. The opposite spins are represented by two arrows, one pointing up, and the other pointing down.

c) Hund's rule
- which states that single electrons with the same spin must sit in each equal orbital before electrons with opposite spins can fill the same orbitals.

We also learned how to use a sublevel diagram, which will help when remembering how to fill orbitals. It is on page 2 of the handout, or uploaded below.

We were then assigned the 'Problems on Electron Configurations' on the back page.

I hope I blogged properly! Have a good night. Yonas, you can scribe