Bell Work 1.Draw Hund’s Rule for: 1.Li 2.O 3.F 2.Write the Electron Configuration for 1.He 2.Be 3.S 4.Zn 3.What does the Aufbau Principle say? 4.PRE-AP ONLY: Draw an Aufbau Chart.

Valence Electrons The outer shell of electrons are called the valence electrons These are important because it’s the outer electrons that interact with each other (form bonds between atoms) There will never be more than 8 valence electrons – Because we fill the d orbital is “buried” under the s & p orbitals, these (s & p orbitals) are always on the outer shell (2 + 6 = 8)

Spherical Radii of the Orbitals

Electron Dot Structures As Chemists we are primarily concerned with the valence electrons Electron Dot Structures give us an easy, quick way of visualizing the valence electrons

Dot Structure for Hydrogen H

Dot Structure for Helium He

Dot Structure for Lithium Li

Dot Structure for Beryllium B

Dot Structure for Oxygen O

Dot Structure for Fluorine F

Class Work 1.Define valence electrons. 2.Draw the electron dot structures for H through Ne 3.Draw Hund’s Rule for 1.B 2.O 3.Na 4.Draw electron configurations for: He, Ne, Mg, Si, Cl, K, Mn, Br