Electromagnetic Spectrum

Atomic Emission Spectrum

Atomic Emission Spectrum

Continuous

Spectrum

Glowing Metal

Photoelectric Effect

Click On Picture

Bohr Model (review)

• Only works for hydrogen atoms• Electrons don’t move in circles• The energy was right, but not because e-

circle like planets

The Hydrogen Spectrum• The three

groups of lines in the hydrogen spectrum correspond to the transitions of electrons from higher energy levels to lower energy levels

The Bohr Ring Atom

n = 3n = 4

n = 2n = 1

Quantum Mechanical Model

• Louis de Broglie -1924– Matter could move

like a wave– Like standing

waves– The vibrations of a

stringed instrument

Schrödinger Equation

Quantum Numbers

• A set of 4 “numbers” that describe an electron

• Tell us– Energy level– Shape of orbital– Orientation of orbital around nucleus– Spin

Principal quantum number• Principal quantum

number (n) – Energy level of the

electron– 7 energy levels– Correspond to 7

periods (rows) of periodic table

Angular Momemtum Quantum Number

• Energy levels are divided into sublevels called orbitals

• An ORBITAL is a region in space where there is a high probability of finding an electron

Orbitals

• Denoted by the letters

s, p, d, and f

• Each orbital can hold 1 or 2 electrons only!

S orbitalsl = 0

1 orbital per energy level

P orbitals 3 orbitals per energy level

P orbitalsl = 1

3 orbitals per energy level

D orbitalsl = 2

5 orbitals per energy

level

F Orbitalsl = 3

7 orbitals per energy level

Magnetic Quantum Number

Magnetic quantum number (m I)

Gives the axis orientation Tells direction in each shape (x,y,z)

Spin Quantum Number

• Describes the direction the electron is spinning.

Spin Quantum Number

• Describes the direction the electron is spinning.

http://www.youtube.com/watch?v=sMt5Dcex0kg

http://www.learner.org/interactives/periodic/elementary_interactive.html

Electron Configuration

We follow 3 rules to get the correct electron configuration for each atom

1. Aufbau Principle

2. Pauli exclusion Principle

3. Hund’s Rule

Energy Levels in atoms

Sublevels Orbitals

Energy Levels in atoms

Sublevels Orbitals