NOTES: 11/17/14
Let’s take a look at the Flame Test from Yesterday.
http://www.youtube.com/watch?v=NEUbBAGw14k
Let’s Review
Atomic Structure
Page 3
Niels Bohr’s Model of the Atom
• Placed the electrons in planetary
orbits around the nucleus.
• Each orbit is called an energy level and
electrons will absorb or release energy as
they move between orbits.
• The energy absorbed or released is in the
form of photons or particles of light
energy.
• The lowest level was known as the ground
state.
Schrödinger Model of the Atom
Mathematical model that predicts the location
of the electrons of an atom:
1. Electrons are found in fuzzy clouds that
predict the most likely place to find the
electron.
2. Clouds are weird shapes
3. Each electron is unique and no two electrons
will have the exact same “address”
Waves:
Electrons and
Light Energy
Objective: To understand the electromagnetic spectrum
and the relationship between energy, wavelength, and
frequency
Electrons are found orbiting the nucleus
and as you move down the periodic table,
the electrons are farther away from the
nucleus.
Each of the rows on the periodic table are
called periods or principle energy
levels.
The electrons in higher principle energy
levels have more energy.
When elements are heated to high
temperatures, some of their electrons
are excited to higher energy levels.
Characteristic colors of light are emitted
when these excited electrons fall back to
their original lower energy level, also
known as periods.
The Wave: Labeling its
parts
Amplitude
Wavelength
A
Crest
Trough
C
D
B
Parts 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 Spectrum
Frequency and
Wavelength
• 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 when it
passes through a glass prism. What visible color has the
longest wavelength & lowest frequency?
Planck’s Constant & Light
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 use!!!
6. What is the energy of a photon of green
light with a frequency of 5.80 x 1014 s-1?
(h=6.626 x 10-34 Js)
E = (6.626 x 10-34 Js) x (5.80 x 1014 s-1)
E = 3.84 x 10-19 J
7. Calculate the wavelength of yellow light emitted
if the frequency is 5.10 x 1014 s-1?
(c = 3.00 x 108 m/s)
C=λ x f
λ
= C/ f
λ= ( 3.00 x 108 m/s) / 5.10 x 1014 Hz
= 5.88 x 10-7 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 6
Chemical &
wavelength
Ba
560 nm
Ca
600 nm
Cu
490 nm
Sr
650 nm
Li
700 nm
Na
580 nm
K
420 nm
Electrons and Light
Waves
• 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.
It takes a quanta of energy (h x v) to
raise the energy from ground state to
excited state and vice versa.
• Electrons in transition from higher to lower
energy levels lose energy and emit light.
Light is just a small part of the
Electromagnetic Spectrum
• Radio waves
• Microwaves
• Infrared
• Visible light
• Ultraviolet
• X-rays
• Gamma rays
Questions:
• Which color of visible light has the shortest
wavelength?
• Which has a lower frequency, visible light or
microwaves?
Wave Calculations
• Formulas:
 c =λ• f
 E=h• 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:
 f = frequency(Hz or s-1)
 λ= wavelength (m)
E= radiant energy (J)
Wave Calculations: Energy &
Frequency
• What is the energy of a
• Formula:
 E=h• f
• Constant:
 h=6.626 x 10-34 J•s
• Variables:
 E= Radiant Energy
• Joules (J)
 f = Frequency
• Hertz (Hz or s-1)
photon of green light with a
frequency of 5.76 x 1014 s-1?
– Given:
• f = 5.76 × 1014 s-1
• h= 6.6262 × 10-34 J•s
– Unknown: E=?
– Equation: E=h• f
– Solution:
• E= (6.6262 × 10-34 J•s)
× (5.76 × 1014 s-1)
• E= 3.82 × 10-19 J (3 s.f)
Wave Calculations: Frequency &
Wavelength
• Calculate the wavelength of
• Formula:
 c =λ• f
• Constant:
 c = 3.0x108 m/s
• Variables:
 λ= Wavelength (m)
 f = Frequency (Hz or s-1)
the yellow light emitted by a
sodium lamp if the frequency
of the light is 5.12x1014 Hz.
o Given:
• f = 5.10x1014 Hz
• c = 3.0x108 m/s
– Unknown:
λ=?
– Equation:
c =λ• f
λ =c /f (rearranged)
– Solution: λ = 3.0x108 m/s
5.12x1014 Hz
λ = 5.86 × 10-7 m
(3 s.f.)
Exit Ticket:
1. What is the wavelength of light emitted if
the frequency is 3.5 x 10 12 s-1 ?
2. What is the frequency if the wavelength is
4.5 meters?
3. What is the energy of a photon of light with
a frequency of 2.5 x 10 12 s-1 ?
4. What is the frequency if the energy is
2.5 x 10 -19 J?
A Closer Look at
the Electron
Where is the Electron?
• In the quantum mechanical model, the electrons
are found outside the nucleus.
• To describe an electron’s location, we can includes
1. Its Energy Level
2. Its Sublevel
3. Its Atomic Orbital
Principle Energy Levels
• The first horizontal row of the periodic table
represents the first or (n=1) principle energy
level.
• Represented by the letter, n
n = 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 Model
•
Sublevels
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
s-Sublevel
sphere
p-Sublevel
dumb bell
This is only one
of the p-sublevel
atomic orbitals.
Since there are 3 orbitals
in the p-Sublevel:
d-Sublevel
Don’t need to memorize these!
f- Sublevel
Don’t need to memorize these!
Summary of the Sublevels
Sublevel
Number of
Atomic Orbitals
Maximum
Number of
Electrons
s
1
2
p
3
6
d
5
10
f
7
14
Atomic 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 Notes
Question #1
1. Which sublevel has a dumbbell
shape?
a)s sublevel
The p-sublevel
has a dumbbell
b)p sublevel
shape, while the
c)d sublevel
s-sublevel has a
d)f sublevel
spherical shape.
Processing Your Notes
Question #2
2. Which sublevels will have the
same shape?
a) 3s and 3p
The letter or
b) 3p and 4p
sublevel
determines the
c) 1s and 2p
shape.
d) 4d and 3s
Processing Your Notes
Question #3
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) 1
b) 3
3rd Row = 3 Energy Levels
c) 11
d) 23
Processing Your Notes
Question #4
4. How many orbitals are found in a
d-sublevel?
Be Careful!
a) 4
The d-sublevel has
b) 5
5 orbitals and holds
10 electrons.
c) 10
You will want to
d) 14
memorize that
table!
Processing Your Notes
Question #5
5. How many electrons can be held
in one atomic orbital?
a) 2
Orbitals are like seats on the bus.
Each seat/orbital will hold 2 electrons
b) 6
c) 10
d) 14
Processing Your Notes
Question #6
6. Which letter does not represent a
current sublevel of an energy level?
a) d
n represents the
b) f
energy level not a
c) n
sublevel.
d) p
Processing Your Notes
Question #7
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) 7
s =1
b) 8
p=3
c) 9
d =5
d) 32
f =7
g=9
Putting It All Together
4
1
2
3
s
s&p
s, p, & d
1
4
9
16
2
8
18
32
s, p, d, & f
Electron Configurations
Electron Configurations represent the location of the
electrons in an atom or ion.
the number
of electrons
2
2
5
1s 2s 2p
the energy
level of the
electron (n)
the sublevel
Processing Your Notes
Question #8
8. How many orbitals are in the fourth
energy level?
For the fourth energy,
a) 4
you have s, p, d and f.
b) 8
s = 1 orbital
p = 3 orbitals
c) 16
d
=
5
orbitals
d) 32
f = 7 orbtials
Add these up!
1 + 3 + 5 +7 = 16
Processing Your Notes
Question #9
9. How many electrons are held in
n=2?
n=2 means the second
a) 2
energy level.
b) 4
s = 2 electrons
p = 6 electrons
c) 8
d) 16
Add these up!
2 + 6 = 8 electrons
Processing Your Notes
Question #10
10. Which of the following sublevels
does not exist?
• On the first energy level, you only
a) 1s
have 1s.
b) 2d • On the second energy level, you
only have 2s and 2p.
c) 3p • On the third energy level, you only
have 3s, 3p, and 3d.
d) 4f
• All four sublevels are on the fourth
energy level.
Processing Your Notes
Question #11
11. Which of the following would be
an expression used to calculate the
number of orbitals based on the
energy level (n)?
2 = 1
n
=
1
n
a) 2n
2 = 4
n
=
2
n
b) n2
n=3
n2 = 9
c) n + 6
n=4
n2 = 16
d) 2n2
Processing Your Notes
Question #12
1s22s22p63s23p4
12. Which element is represented by
this electron configuration?
a) sodium
Add up the
exponents!
b) sulfur
c) argon
Since it is neutral,
d) selenium
protons = electrons.
Processing Your Notes
Question #13
1s22s22p63s23p4
13. What is the highest energy level in
this electron configuration?
a) 2
Energy level
represented by the
b) 3
coefficient or the big
c) 4
number.
d) 6
Processing Your Notes
Question #14
1s22s22p63s23p4
14. How many electrons are found in
the s-sublevel?
a) 2
2+2+2=
b) 4
6
c) 6
d) 8
Processing Your Notes
Question #15
1s22s22p63s23p64s23d104p1
15. Which sublevel has the most
electrons?
a) s
p = 13 electrons
d = 10 electrons
b) p
s = 8 electrons
c) d
d) f
Processing Your Notes
Question #16
1s22s22p63s23p64s23d104p1
16. How many electrons are in the
highest energy level?
a) 1
The “coefficient”
determines the
b) 2
energy, so 4s and 4p
c) 3
are both on the
d) 13
highest energy level.
Processing Your Notes
Question #17
1s22s22p63s23p64s23d104p1
17. What element is represented by
the electron configuration?
a) titanium
Add up the
exponents!
b) copper
c) gallium
Since it is neutral,
d) germanium protons = electrons.
Rule #1: Pauli’s Exclusion Principle
Each atomic orbital can hold
two electrons.
Sublevel
# of Orbitals
Max # of
Electrons
s
p
d
f
1
3
5
7
2
6
10
14
Rule #2: Aufbau Principle
Electrons will fill the atomic
orbital with the lowest energy
first.
2
2
6
2
6
2
10
5
1s 2s 2p 3s 3p 4s 3d 4p
Lowest Energy  Highest Energy
Blocks in The Periodic Table
Row
#
1
2
3
4
5
6
7
= s block
= p block
= d block
= f block
Sample Electron
Configurations
• Hydrogen  1s1
• Beryllium  1s22s2
• Fluorine  1s22s22p5
• Chlorine  1s22s22p63s23p5
• Potassium  1s22s22p63s23p64s1
Sample Electron
Configurations
•
•
•
•
•
Hydrogen __
Beryllium __ __
Fluorine __ __ __ __ __
Chlorine __ __ __ __ __ __ __ __ __
Potassium __ __ __ __ __ __ __ __ __
__