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## Chemistry Warm Up Some Dimensional Analysis Review.

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### Chemistry Warm Up Some Dimensional Analysis Review. PLEASE SHOW YOUR WORK USING CONVERSION FACTORS AND DIMENSIONAL ANALYSIS If 6.02 x 1023 atoms of carbon have a mass ... – PowerPoint PPT presentation

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Title: Chemistry Warm Up Some Dimensional Analysis Review.

1
Chemistry Warm Up Some Dimensional Analysis
Review.
AND DIMENSIONAL ANALYSIS
• If 6.02 x 1023 atoms of carbon have a mass of
12.0 grams, what the mass of 1.51 x 1023 atoms
of carbon atoms. Hint set up the equality that
you know. Make two conversion factors and use one
to solve the problem. Check your work using
dimensional analysis.
• 2. How many atoms are there in sample of carbon
that weighs 30.0grams?
• 3. How many atoms are there in a sample that
weighs 3.60 x 102 grams?

2
Chemistry Warm Up Periodic Table Scavenger Hunt
• The periodic table is arranged by atomic number,
not by atomic mass. Find a sequence of three
elements that are arranged by atomic number but
not by atomic mass.
• 2. Find three elements whose symbols dont seem
to have anything to do with their names. Write
the name and the symbol for each.
• 3. There are two rows at the bottom of the
periodic table. Use the atomic number to figure
out where they fit in to the periodic table.
• 4. What would the periodic table look like if
those two rows were inserted in order of their
atomic number? Make a sketch.

3
Chapter5.1 Models of the Atom
California State Science Standards Chemistry 1.
The periodic table displays the elements in
increasing atomic number and shows how
periodicity of the physical and chemical
properties of the elements relates to atomic
structure. As a basis for understanding this
concept g. Students know how to relate the
position of an element in the periodic table to
its quantum electron configuration and to its
reactivity with other elements in the table. i.
Students know the experimental basis for the
development of the quantum theory of atomic
structure and the historical importance of the
Bohr model of the atom.
4
Chapter5.1 Models of the Atom
5
Development of Atomic Models Rutherfords Model
• Dense central Nucleus
• Electrons orbit like planets
• Atom mostly empty space
• Does not explain chemical behavior of atoms

6
The Bohr Model
• Electrons orbit the nucleus
• Specific circular orbits
• Quantum energy to move from one level to
another

7
The Bohr Model
• Energy level like rungs of the ladder
• The electron cannot exist between energy levels,
just like you cant stand between rungs on a
• A quantum of energy is the amount of energy
required to move an electron from one energy
level to another

8
The Bohr Model
Energy level of an electron analogous to the
But, the rungs on this ladder are not evenly
spaced!
9
Quantum Mechanical Model
• Energy quantized comes in chunks.
• A quantum is the amount of energy needed to move
from one energy level to another.
• Since the energy of an atom is never in between
there must be a quantum leap in energy.
• 1926 Erwin Schrodinger equation described the
energy and position of electrons in an atom

10
Quantum Mechanical Model
Things that are very small behave differently
from things big enough to see. The quantum
mechanical model is a mathematical solution It
is not like anything you can see.
11
Quantum Mechanical Model
Has energy levels for electrons. Orbits are not
circular. It can only tell us the probability of
finding an electron a certain distance from the
nucleus.
12
Atomic Orbitals
Energy levels (n1, n2) Energy sublevels
different shapes The first energy level has one
sublevel 1s orbital -spherical
13
Atomic Orbitals
The second energy level has two sublevels, 2s
and 2p
There are 3 p-orbitals
14
Atomic Orbitals
The third energy level has three sublevels, 3s
3p
And 5 3d orbitals
15
Atomic Orbitals
The forth energy level has four sublevels, 4s
4p
4d orbitals And seven 4f orbitals
16
Atomic Orbitals The principal quantum number
(energy level) equals the number sublevels
17
5.2 Electron Arrangement in Atoms
Electron Configuration Electrons and nucleus
interact to produce most stable
arrangement Lowest energy configuration
18
3 rules
Aufbau Principle Electrons fill the lowest energy
orbitals first
Hydrogen has 1 electron
1s1
19
3 rules
Pauli Exclusion Principal- two electrons per
orbital (one spin up, one spin down)
Boron has 5 electrons
1s2
2s2
2p1
20
3 rules
Hunds rule- In orbitals with equal energy
levels, arrange spin to maximize electrons with
the same spin
1s22s22p3
Nitrogen has 7 electrons
Hunds Rule Separate the three 2p elecrons into
the three available 2p orbitals to maximize the
electrons with the same spin.
21
Conceptual Problem p135
Electron Configuration for Phosphorus (atomic
15)
1s2
2s2
2p6
3s2
3p3
22
Practice Problem 8a p135
Electron Configuration for Carbon (atomic number
6)
1s2
2s2
2p2
23
Practice Problem 8b p135
Electron Configuration for Argon (atomic 18)
1s2
2s2
2p6
3s2
3p6
24
Practice Problem 8c p135
Electron Configuration for Nickel (atomic 28)
1s2
2s2
2p6
3s2
3p6
4s2
3d8
25
Practice Problem 9a p135
Electron Configuration for Boron (atomic 5)
1s2
2s2
2p1
How many unpaired electrons? 1
26
Practice Problem 8c p135
Electron Configuration for Silicon (atomic 14)
1s2
2s2
2p6
3s2
3p2
How many unpaired electrons? 2
27
Exceptions to the Aubau Rule
Copper atomic number29
1s2
2s2
2p6
3s2
3p6
4s2
3d9
This is the expected electron configuration
28
Exceptions to the Aubau Rule
Copper atomic number29
1s2
2s2
2p6
3s2
3p6
4s1
3d10
Half-filled and filled sublevels are more stable,
even if it means stealing an electron from a
nearby sublevel
This is the actual electron configuration.
29
Exceptions to the Aubau Rule
Chromium atomic number24
1s2
2s2
2p6
3s2
3p6
4s2
3d4
This is the expected electron configuration
30
Exceptions to the Aubau Rule
Chromium atomic number24
1s2
2s2
2p6
3s2
3p6
4s1
3d5
Half-filled and filled sublevels are more stable,
even if it means stealing an electron from a
nearby sublevel
This is the actual electron configuration.
31
5.3 Physics and the Quantum Mechanical Model
Or, How do they get all those colors of neon
lights?
32
Goals
Describe the relationship between wavelength and
frequency of light Identify the source of atomic
emission spectra Explain how frequency of
emitted light are related to changes in electron
energies Distinguish between quantum mechanics
and classical mechanics
33
Quick review of wave terminology
Amplitude height of wave Wavelength distance
between crests Frequency number of crests to
pass a point per unit of time
34
Light waves
Amplitude height of wave Wavelength distance
between crests Frequency number of crests to
pass a point per unit of time
For light, the product of frequency and
wavelength speed of light, c Frequency
Wavelength 3.00 x 108 So, as the frequency of
light increases, the wavelength decreases
35
Electromagnetic Spectrum
Visible light is only part of the electromagnetic
spectrum
36
Wavelength of Light p140
Sample Problem What is the wavelength of yellow
light from a sodium lamp if the frequency is 5.10
x 1014 Hz (Hz s-1)
Wavelength frequency 3.00x108m/s Wavelength
3.00x10-8 m/s / frequency Wavelength
3.00x108m/s / 5.10x1014 s-1 Wavelenght 5.88 x
10-7 m
37
Wavelength of Light p140
14What is the wavelength of radiation if the
frequency is 1.50x1013 Hz (Hz s-1)? Is this
longer or shorter than the wavelenght of red
light? Wavelength frequency
3.00x108m/s Wavelength 3.00x108 m/s /
frequency Wavelength 3.00x108m/s / 1.50x1013
s-1 Wavelength 2.00 x 10-5 m Longer than red
lightwhich if between 10-6 and 10-7 m
38
Wavelength of Light p140
15 What is the frequency of radiation if the
wavelength is 5.00x10-8 Hz (Hz s-1) In what
range of the electromagnetic specrum is
this? Wavelength frequency 3.00x108m/s frequen
cy 3.00x108 m/s / wavelength frequency
3.00x108m/s / 5.00x10-8m Frequency 6.00 x 1015
s-1 ultraviolet
39
Atomic Spectra
When atoms absorb energy, Electrons move to
the lower energy level, they emit light Each
energy level produces a certain frequency of
light resulting in an emission spectrum
40
Atomic Spectra
Emission spectra are like a fingerprint of the
element We know what stars are made of by
comparing their emission spectra to that of
elements we find on earth
41
Explanation of Atomic Spectra
Emission spectra like a fingerprint of the
element We know what stars are made of by
comparing their emission spectra to that of
elements we find on earth