notes: 11/17/14 let’s take a look at the flame test from yesterday

NOTES: 11/17/14NOTES: 11/17/14

http://www.youtube.com/watch?v=NEUbBAGw14k

Let’s take a look at the Flame Test from Yesterday.



Let’s Review Atomic Structure

Page 4

Niels Bohr’s Model Niels Bohr’s Model of the of the AtomAtom

• Placed the Placed the electrons in planetary electrons in planetary orbitsorbits around the nucleus. around the nucleus. • Each orbit is called an Each orbit is called an energy levelenergy level and and

electrons will absorb or release electrons will absorb or release energyenergy as they move between orbits. as they move between orbits.

• The The energyenergy absorbed or released is in absorbed or released is in the form of the form of photons or particles of photons or particles of lightlight energy. energy.

• The lowest level was known as the The lowest level was known as the ground stateground state..

Schrödinger Model Schrödinger Model of the of the AtomAtomMathematical model that Mathematical model that predicts the predicts the

locationlocation of the electrons of an atom: of the electrons of an atom:1.1. Electrons are found in Electrons are found in fuzzy clouds fuzzy clouds that that

predict the most likely place to find the predict the most likely place to find the electron.electron.

2.2.CloudsClouds are weird shapes are weird shapes3.3. Each electron is Each electron is uniqueunique and no two and no two

electrons will have the exact same electrons will have the exact same “address”“address”

Waves:Waves: Electrons and Electrons and Light EnergyLight Energy

Objective: To understand the electromagnetic spectrum and the relationship between energy, wavelength, and frequency

Electrons are found orbiting the Electrons are found orbiting the nucleus and as you move down the nucleus and as you move down the periodic table, the electrons are periodic table, the electrons are fartherfarther away from the nucleus. away from the nucleus.

Each of the rows on the periodic Each of the rows on the periodic table are called table are called periods or periods or principle energy levelsprinciple energy levels. .

The electrons in higher principle The electrons in higher principle energy levels have energy levels have more energy. more energy.

When elements are heated to high When elements are heated to high temperatures, some of their temperatures, some of their electronselectrons are excited to are excited to higher higher energy levelsenergy levels..

Characteristic colors of Characteristic colors of lightlight are are emitted when these excited emitted when these excited electrons fall back to their original electrons fall back to their original lower energy level, also known as lower energy level, also known as periods.periods.

The Wave: Labeling its The Wave: Labeling its partsparts

A C

D

B

AmplitudAmplitudeeWavelengtWavelengthh

CrestCrestTrougTroughh

Parts of the WaveParts of the Wave• 5.Amplitude- the wave’s height from origin

to crest (or from origin to trough) 6. Wavelength- the distance between two

crests in a wave (or between two troughs) 7.Frequency- number of wave cycles to

pass a given point per unit of time• 8.hertz- the SI unit for frequency in cycles

per second• 9.Speed of light- product of frequency and

wavelength equaling 3.0 X 108 m/s• 10.Spectrum- range of wavelengths of

electromagnetic radiation

Electromagnetic Electromagnetic SpectrumSpectrum

Frequency and Frequency and WavelengthWavelength

• As the frequency increases ( more waves per second) the wavelength decreases (because waves are closer together).

2.White light separates into a rainbow of colors 2.White light separates into a rainbow of colors when it passes through a glass prism. What visible when it passes through a glass prism. What visible

color has the longest wavelength & lowest color has the longest wavelength & lowest frequency?frequency?

Planck’s Constant & Planck’s Constant & Light QuantaLight Quanta

• Max Planck’s Constant: showed mathematically that the amount of radiant energy (E) absorbed/emitted is proportional to the frequency of radiation

• Energy of photons quantized by E = h x f

• In 1905 Einstein proposed light could be described as quanta of energy that behave as if particles.

• Light quanta are called photons.

Three Equations we Three Equations we use!!!use!!!

Change f to λ

6. What is the 6. What is the energyenergy of a photon of of a photon of green light with a frequency of 5.80 x green light with a frequency of 5.80 x 10101414 s s-1-1? ? (h=6.626 x 10(h=6.626 x 10-34-34 Js) Js)

E = (6.626 x 10E = (6.626 x 10-34-34 Js) x (5.80 x 10 Js) x (5.80 x 1014 14 ss-1-1))

E = 3.84 x 10E = 3.84 x 10-19 -19 JJ

7. Calculate the 7. Calculate the wavelengthwavelength of yellow light emitted of yellow light emitted if the frequency is 5.10 x 10if the frequency is 5.10 x 101414 s s-1-1? ? ((cc = 3.00 x 10 = 3.00 x 1088 m/s) m/s)

C = C = x f x f

= C/ f= C/ f

= (= (3.00 x 103.00 x 1088 m/s) / 5.10 x 10 m/s) / 5.10 x 101414 Hz Hz = 5.88 x 10= 5.88 x 10-7-7 m/s m/s

8. Calculate the energy of a photon with a wavelength of 6.7 x 10-7 m?

E=hc λ

E = (6.63 x 10-34) (3.00 X 108 m/s ) 6.7 x 10-7 m

E = 3.0 x10-19 Joules

Homework: Calculations on page 6Chemical & wavelength

Ba560 nm

Ca600 nm

Cu490 nm

Sr650 nm

Li700 nm

Na580 nm

K420 nm

Electrons and Light Electrons and Light WavesWaves

• Every element emits light when excited by the passage of an electric discharge through its gas or vapor.

• Atomic Emission Spectrum – light emitted by the element when passed through a prism.

• Electrons in transition from higher to Electrons in transition from higher to lower energy levels lose energy and lower energy levels lose energy and emit light.emit light.

It takes a quanta of energy (h x v) It takes a quanta of energy (h x v) to raise the energy from ground to raise the energy from ground state to excited state and vice state to excited state and vice versa.versa.

Light is just a small part of Light is just a small part of the Electromagnetic the Electromagnetic SpectrumSpectrum•Radio wavesRadio waves•MicrowavesMicrowaves•InfraredInfrared•Visible lightVisible light•UltravioletUltraviolet•X-raysX-rays•Gamma raysGamma rays

Questions:Questions:• Which color of visible light has the shortest

wavelength?• Which has a lower frequency, visible light or

microwaves?

Wave CalculationsWave Calculations• Formulas:

c =λ• f f E=h• f f

• Constants: c = 3.0 × 108 m/s

• Speed of light h= 6.626 × 10-34 J•s

• Plank’s Constant• Relates energy of a photon to

frequency

• Variables:Variables: f f = frequency(Hz or = frequency(Hz or

ss-1-1)) λλ= = wavelength (m)wavelength (m)E= radiant energy (J)E= radiant energy (J)

Wave Calculations: Energy & Wave Calculations: Energy & FrequencyFrequency

• Formula: E=h• f f

• Constant: h=6.626 x 10-34 J•s

• Variables: E= Radiant Energy

• Joules (J) f f = Frequency

• Hertz (Hz or s-1)

• What is the energy of a What is the energy of a photon of green light photon of green light with a frequency of 5.76 with a frequency of 5.76 x 10x 101414 s s-1-1?? – Given:Given:

• f f = 5.76 × 10= 5.76 × 101414 s s-1-1

• h= 6.6262 × 10h= 6.6262 × 10-34-34 J J••ss– Unknown:Unknown: E=?E=?– Equation:Equation: E=h E=h•• f f – Solution:Solution:

•E= (6.6262 × 10E= (6.6262 × 10-34-34 J J••s) s) × (5.76 × 10× (5.76 × 101414 s s-1-1))•E= 3.82 × 10E= 3.82 × 10-19-19 J (3 J (3

s.f)s.f)

Wave Calculations: Frequency Wave Calculations: Frequency & Wavelength& Wavelength

• Formula: c =λ• f f

• Constant: c = 3.0x108 m/s

• Variables: λ= Wavelength (m) f f = Frequency (Hz or s-1)

• Calculate the wavelength Calculate the wavelength of the yellow light emitted of the yellow light emitted by a sodium lamp if the by a sodium lamp if the frequency of the light is frequency of the light is 5.12x105.12x1014 14 Hz.Hz.

o Given:• f f = 5.10x1014 Hz• c = 3.0x108 m/s

– Unknown:Unknown: λ = ??– Equation:Equation: c =λ• f f λ ==c c //f f (rearranged)(rearranged)

– Solution:Solution: λ = 3.0x10= 3.0x1088 m/s m/s 5.12x105.12x1014 14 HzHz

λ = 5.86 × 10= 5.86 × 10-7-7 m (3 s.f.) m (3 s.f.)

1.1. What is the wavelength of light emitted What is the wavelength of light emitted if the frequency is 3.5 x 10 if the frequency is 3.5 x 10 1212 s s-1 -1 ??

2.2. What is the frequency if the What is the frequency if the wavelength is 4.5 meters?wavelength is 4.5 meters?

3.3. What is the energy of a photon of light What is the energy of a photon of light with with a frequency of 2.5 x 10 a frequency of 2.5 x 10 1212 s s-1 -1 ??

4.4. What is the frequency if the energy is What is the frequency if the energy is 2.5 x 10 2.5 x 10 -19 -19 J?J?

Exit Ticket:Exit Ticket:

The Modern The Modern Atomic Theory: Atomic Theory: A Closer Look A Closer Look at the Electronat the Electron

Where is the Electron?Where is the Electron?• In the quantum mechanical model, the electrons

are found outsideoutside the nucleus.

• To describe an electron’s location, we can includes 1. Its Energy Level2. Its Sublevel3. Its Atomic Orbital

Principle Energy Principle Energy LevelsLevels

• The first horizontal row of the periodic table represents the first or (n=1) principle energy level.

• Represented by the letter, nn = 1 First Energy Level

• Each new row on the periodic table starts a new energy level.

• Each energy level has a different number of sublevels, a different number of orbitals, and a different number of electrons.

The Bohr ModelThe Bohr Model

SublevelsSublevels• Based on the number of elements in our Periodic

Table, there are four sublevels.s, p, d, f

• Each sublevel has a unique shape.

• The size of the sublevel depends on the energy level.

Higher Energy Level = Bigger Sublevel

ss-Sublevel-Sublevelspheresphere

pp--SublevelSublevel

dumb belldumb bell

This is only one of the p-

sublevel atomic

orbitals.

http://www.dlt.ncssm.edu/tiger/Flash/structure/P-orbitalDiagram.html

Since there are 3 Since there are 3 orbitals in the p-orbitals in the p-

Sublevel:Sublevel:

dd-Sublevel-Sublevel

Don’t need to memorize these!

http://upload.wikimedia.org/wikipedia/commons/e/e1/D_orbitals.svg

ff- Sublevel- Sublevel

Don’t need to memorize these!

Summary of the Summary of the SublevelsSublevels

SublevelSublevel Number of Number of Atomic OrbitalsAtomic Orbitals

Maximum Maximum Number of Number of ElectronsElectrons

ss 11 22

pp 33 66

dd 55 1010

ff 77 1414

Atomic OrbitalsAtomic Orbitals• All electrons are located in an atomic orbital or

orbital.• An atomic orbital represents the area in which

there is a 90% chance of finding an electron.• Each atomic orbital can hold two electrons.• Inside these orbitals, electrons take random and

unpredictable paths.

Processing Your NotesProcessing Your NotesQuestion #1Question #1

1. Which sublevel has a dumbbell shape?

a)s sublevelb)p sublevelc)d subleveld)f sublevel

The p-sublevel has a dumbbell

shape, while the s-sublevel has a spherical

shape.


2. Which sublevels will have the same shape?

a) 3s and 3pb) 3p and 4pc) 1s and 2pd) 4d and 3s

The letter or sublevel

determines the shape.


3. Sodium is found on the third row or Period 3 of the periodic table. How many energy levels do the electrons of a sodium atom occupy?

a) 1b) 3c) 11d) 23

3rd Row = 3 Energy Levels


5. How many electrons can be held in one atomic orbital?

a) 2b) 6c) 10d) 14

Orbitals are like seats on the bus. Each seat/orbital will hold 2 electrons


4. How many orbitals are found in a

d-sublevel? a) 4b) 5c) 10d) 14

Be Careful! The d-sublevel has 5 orbitals and holds 10

electrons.You will want to memorize that

table!


6. Which letter does not represent a current sublevel of an energy level?

a) db) fc) nd) p

n represents the energy level not a sublevel.


7. As scientists create new elements, we will need to add new sublevels to the four existing sublevels. In fact, the next sublevel will be called g. After looking at the trend in the number of orbitals for the current sublevels, how many orbitals would you predict would exist in a g-sublevel?

a) 7b) 8c) 9d) 32

s =1p = 3d = 5f = 7g = 9

Putting It All TogetherPutting It All Together

1

s

1

2

2

s & p

4

8

3

s, p, & d

9

18

4

s, p, d, & f

16

32

Electron ConfigurationsElectron ConfigurationsElectron Configurations represent the location of the electrons in an atom or ion.

1s22s22p5

the energy level of the electron (n)

the sublevel

the number of electrons


8. How many orbitals are in the fourth energy level?

a) 4b) 8c) 16d) 32

For the fourth energy, you have s,

p, d and f.s = 1 orbital

p = 3 orbitalsd = 5 orbitalsf = 7 orbtialsAdd these up!

1 + 3 + 5 +7 = 16


9. How many electrons are held in n=2?

a) 2b) 4c) 8d) 16

n=2 means the second energy level.

s = 2 electronsp = 6 electrons

Add these up!2 + 6 = 8 electrons


10. Which of the following sublevels does not exist?

a) 1sb) 2dc) 3pd) 4f

• On the first energy level, you only have 1s.

• On the second energy level, you only have 2s and 2p.

• On the third energy level, you only have 3s, 3p, and 3d.

• All four sublevels are on the fourth energy level.


1s22s22p63s23p4

12. Which element is represented by this electron configuration?a) sodiumb) sulfur c) argond) selenium

Add up the exponents!

Since it is neutral, protons = electrons.


1s22s22p63s23p4

13. What is the highest energy level in this electron configuration?a) 2b) 3 c) 4d) 6

Energy level represented by

the coefficient or the big number.


1s22s22p63s23p4

14. How many electrons are found in the s-sublevel?a) 2b) 4c) 6d) 8

2 + 2 + 2 = 6


1s22s22p63s23p64s23d104p1

15. Which sublevel has the most electrons?a) sb) p c) dd) f

p = 13 electronsd = 10 electronss = 8 electrons


1s22s22p63s23p64s23d104p1

16. How many electrons are in the highest energy level?a) 1b) 2 c) 3d) 13

The “coefficient” determines the

energy, so 4s and 4p are both on

the highest energy level.


1s22s22p63s23p64s23d104p1

17. What element is represented by the electron configuration?a) titaniumb) copperc) galliumd) germanium

Add up the exponents!

Since it is neutral, protons = electrons.

Rule #1: Rule #1: Pauli’s Exclusion Principle

Each atomic orbital can hold two electrons.

SublevelSublevel # of Orbitals# of Orbitals Max # of Max # of ElectronsElectrons

ss 11 22pp 33 66dd 55 1010ff 77 1414

Rule #2: Rule #2: Aufbau Principle

Electrons will fill the atomic orbital with the lowest energy

first.

1s22s22p63s23p64s23d104p5Lowest Energy Highest

Energy

Blocks in The Periodic Blocks in The Periodic TableTable

= s block = d block= p block = f block1

234567

Row #

Sample Electron Sample Electron ConfigurationsConfigurations

• Hydrogen 1s1

• Beryllium 1s22s2

• Fluorine 1s22s22p5

• Chlorine 1s22s22p63s23p5

• Potassium 1s22s22p63s23p64s1

Sample Electron Sample Electron ConfigurationsConfigurations

• Hydrogen __• Beryllium __ __ • Fluorine __ __ __ __ __ • Chlorine __ __ __ __ __ __ __ __ __ • Potassium __ __ __ __ __ __ __ __ __

__

notes: 11/17/14 let’s take a look at the flame test from yesterday

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