The Quantum Model

Energy as wave and particle

Quantum Mechanics Explains how ‘small’ particles move

Sorry Mr. Smith

What is light? Wave

Particle

Photoelectric Effect

The Electromagnetic Spectrum

c =

If energy is constant then: (wavelength), in meters, is inversely proportional to (frequency), measured in hertz or 1/s

OR

As wavelength increases frequency decreases

E = h

If energy is constant then: h is Planck’s constant, (J x s) (frequency), measured in hertz or 1/s E is energy in Joules (J)

Red Light

Violet Light

• Low frequency

• Long wavelength

• High frequency

•Short wavelength

Wave Comparisonnm = 1 x 10-9 m

Example Problem Refer to #1 on your Worksheet. On page 7 of

hw packet.

Bohr Model

Electrons are a HUGE deal in chemistry

Responsible for chem rxns

Today: How many are there Where do they reside

Periodic Table

Electron Configurations Electron configurations are...

Electron Configuration Vocab Principle Energy Level

correlates to the period (1-7), periods go from left to right across the periodic table

Sublevel are located in the principle energy level. There are 4 that we

will talk about s, p, d and f.

Orbital located in the sublevel. Where electrons are most likely to be

found 1 ORBITAL HOLDS 2 ELECTRONS

Writing Electron Configurations Principle Energy Level[sublevel]number of electrons

OR a[b]c

Get your periodic table! Start from left to right!

Orbital Diagrams Tool for creating electron

configurations

2 dimensional representation of where electrons are in an atom

Aufbau Principle electrons are added to the lowest available

energy level. Hydrogen as an example:

Pauli Exclusion Principle each orbital can hold two electrons those electrons must have opposite spins

spin is represented by the arrow facing up or down.

Hund’s Rule Orbitals of equal energy are occupied by one

electron before 2 electrons occupy 1 orbital. The second electron is added after all orbitals have one electron

Aufbau Diagram

The Periodic Table1s 1s

2s 2p

3s 3p

4s 3d 4p

5s 4d 5p

6s 5d 6p

7s 6d 7p

4f

5f

Noble Gas Configuration – Short cut Locate the element on the PT

Trace backward to the nearest noble gas

Put that noble gas in [] (brackets)

Fill in remaining electrons

P orbitals in more detail p sublevel

3 orbitals x, y & z

Work like a coordinate plane Atoms are 3-D

Valence Electrons Electrons in the HIGHEST energy level (n)

Electrons that interact during chem rxns

Always in the s & p sublevels

Finding Valence Electrons Locate the highest

energy level Count the electrons

present Orbital diagrams

SUPER helpful

Example: Sulfur How many valence e’s?

Stability – Hund’s Rule Exceptions to e configs

In the d-block (yo) Almost ½ filled d-block Almost full d-block

It is more stable for atoms to have 2 half filled sublevels Compared to 1 full and 1

partially filled Example: Chromium