Do Now:Take out your vocab1. What is light?2. How is it related to x-rays or radio waves?

Wave-Particle Duality

What is light?•Light consists of electromagnetic waves.•Electromagnetic radiation includes:

Electromagnetic Radiation• Consist of particles that move as waves of energy

Waves can be described by amplitude, wavelength, and frequency

• Amplitude – height of the wave• Wavelength(l) – distance between crests• Frequency(n) – number of wave cycles to pass a given point in a certain amount of time

Draw a Wave in the Box

1. Measure the wavelength and amplitude.2. Then draw waves in box B of the same

amplitude but greater frequency.3. Measure the wavelength and amplitude. 4. What happened to the wavelength from A

to B. 5. How are wavelength and frequency

related? How is energy related to frequency?

• Using the equation: c = ln• Find the wavelength of a radio

wave that is brodcasted at 95.5 x 106Hz

• Find the frequency of blue light. Blue light has a wavelength of 6.43x 10-7m.

• Which are not visible?• Which are more energetic than visible light? How do you know?

• What do all the rays in the electromagnetic spectrum have in common?

Do Now:1. Compare the atomic models of

Thomson and Rutherford.2. Explain the Bohr model of the

atom3. What colors make up the

continuous spectrum of visible light?

Neils Bohr• Studied hydrogen and its emission spectrum

• Proposed the Planetary Model• Electrons orbit the nucleus• Electrons travel in successively larger orbits and

when an electron jumps from an outer orbit to an inner one, it emits light.

CONTINUOUS SPECTRUM

• Each element emits a unique collection of lines. • The atomic spectrum can be used to determine

the composition of a material, since it is different for each element of the periodic table.

Why do we so only certain lines of color?

• Each color has a specific wavelength• Each wavelength is associated with a specific

amount of energy• That energy is released when the electron

jumps from a higher energy level to a lower energy level.

• Only specific energy levels are allowed in the atom! Energy of the atom is quantized!

Energy of quantum of electromagnetic radiation is proportional to frequency

So the electron behaves like a wave, but where is it?

• Werner Heisenberg proposed Heisenberg uncertainty principle

• There is a limitation to knowing where the electron is (its position) and where its going (its momentum)

• Erwin Schrodinger developed a mathematical equation to describe the electron’s wave-like behavior

1. Probability of finding electron at different points is calculated

• Some points will have higher probability than others

2. If connect all points of high probability, three dimensional shapes are formed

3. The most probable place to find the electron will be some place in that shape

Atomic orbitals

Zip Code

07080First digit (0-9) represents a group of states in the US. 0 is northeastern states and 9 is western states

Second and third numbers represent a region in that group, perhaps a large city

The fourth and fifth digits representing a group of delivery addresses within that region

• Quantum numbers are used to describe locations of high probability of finding the electrons

1s __2s __2p __ __ __3s __3p __ __ __4s __3d __ __ __ __ __4p __ __ __5s __4d __ __ __ __ __5p __ __ __6s __4f __ __ __ __ __ __ __5d __ __ __ __ __6p __ __ __7s __5f __ __ __ __ __ __ __6d __ __ __ __ __ Orbital Diagram

1. Assign electrons to an Energy Level

2. Next to a sublevel:

s

p

d

f

3. Last to an orbital.

Atomic Orbitals• Region around nucleus where

electrons are likely to be found• Each orbital holds two electrons• These electrons have opposite spin

1s __2s __2p __ __ __3s __3p __ __ __4s __3d __ __ __ __ __4p __ __ __5s __4d __ __ __ __ __5p __ __ __6s __4f __ __ __ __ __ __ __5d __ __ __ __ __6p __ __ __7s __5f __ __ __ __ __ __ __6d __ __ __ __ __

Follow 3 rules to configure the electrons

1. Aufbau Principle - electrons fill orbitals starting at the lowest available (possible) energy states before filling higher states

2. Pauli Exclusion Principle - two electrons cannot share the same set of quantum numbers within the same system. Therefore, there is room for only two electrons in each orbital and the electrons have opposite spin.

3. Hund’s Rule – in equal energy orbitals, arrange the electrons to achieve the maximum number of unpaired electrons.