Bell Work

1. Draw Hund’s Rule for:1. Li2. O3. F

2. Write the Electron Configuration for 1. He2. Be3. S4. 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 Work1. Define valence electrons.2. Draw the electron dot structures for H

through Ne3. Draw Hund’s Rule for

1. B2. O3. Na

4. Draw electron configurations for: He, Ne, Mg, Si, Cl, K, Mn, Br