The Quantum Model Energy as wave and particle
Mar 27, 2015
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