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Transcript 
Daily Quiz
Daily Quiz
1. Where is the proton located?
A.In the nucleus
B.In a cloud around the nucleus
C.Both places
D.Nowhere
E. Different in different elements
Daily Quiz
2. What is the charge on an
electron?
A. Positive
B. Negative
C. Zero
D. Changes with ionization
Daily Quiz
3. What is the mass of a
neutron?
A. 1840 x the mass of a proton
B. 1/1840th the mass of a proton
C. Same as the mass of a proton
D. Zero
E. Changes with gravitation
Daily Quiz
4. J.J. Thompson measured the
mass of the electron using a
A. balance beam scale
B. spring scale
C. sheet of gold foil
D. magnet
E. chocolate chip cookie
Daily Quiz
1. Where is the proton located?
A.In the nucleus
B.In a cloud around the nucleus
C.Both places
D.Nowhere
E. Different in different elements
Daily Quiz
1. Where is the proton located?
A.In the nucleus
B.In a cloud around the nucleus
C.Both places
D.Nowhere
E. Different in different elements
Daily Quiz
2. What is the charge on an
electron?
A. Positive
B. Negative
C. Zero
D. Changes with ionization
Daily Quiz
2. What is the charge on an
electron?
A. Positive
B. Negative
Daily Quiz
3. What is the mass of a
neutron?
A. 1840 x the mass of a proton
B. 1/1840th the mass of a proton
C. Same as the mass of a proton
D. Zero
E. Changes with gravitation
Daily Quiz
3. What is the mass of a
neutron?
A. 1840 x the mass of a proton
B. 1/1840th the mass of a proton
C. Same as the mass of a proton
D. Zero
E. Changes with gravitation
Daily Quiz
4. J.J. Thompson measured the
mass of the electron using a
A. balance beam scale
B. spring scale
C. sheet of gold foil
D. magnet
E. chocolate chip cookie
Daily Quiz
4. J.J. Thompson measured the
mass of the electron using a
A. balance beam scale
B. spring scale
C. sheet of gold foil
D. magnet
E. chocolate chip cookie
Homework
Page 104, problems 15, 16, 17, 21
What you will learn today:
•What do atomic number and
atomic mass tell you?
•How do isotopes relate to atomic
mass?
•How is an AMU defined? Why is
it not exactly the mass of a
proton or a neutron?
Hydrogen
1
H
1.008
Hydrogen
atomic number
1
H
1.008
Hydrogen
atomic number
1
H
atomic mass
1.008
Hydrogen
atomic number
1
number of protons
H
atomic mass
1.008
Hydrogen
atomic number
1
number of protons
number of electrons
H
atomic mass
1.008
Hydrogen
atomic number
1
number of protons
number of electrons
H
atomic mass
1.008
heavy particles
Hydrogen
atomic number
1
number of protons
number of electrons
H
atomic mass
1.008
heavy particles
(protons + neutrons)
atomic number
atomic mass
atomic number
= number of protons
= number of electrons
atomic mass
atomic number
= number of protons
= number of electrons
atomic mass
= average # of heavy particles
= protons + neutrons.
Tomorrow’s
daily quiz will
be on this!
A
B
Element
Atomic
Number
Pb
82
Protons
Electrons
8
C
30
D
26
E
11
Atomic Mass Unit
1/
12
1 AMU =
the mass
of a carbon atom.
How come atomic masses
aren’t whole numbers?
Atomic Mass Unit
1/
12
1 AMU =
the mass
of a carbon atom.
Proton = 1.007276 AMU
Neutron = 1.008665 AMU
Electron = 0.000549 AMU
How come atomic masses
aren’t whole numbers?
Atoms sometimes have extra
neutrons
Extra neutrons don’t do anything
chemically…
…but they’re heavy!
How come atomic masses
aren’t whole numbers?
An isotope is an atom with a
different number of neutrons
The mass number is the exact
number of protons + neutrons in
an atom.
Five-Minute Assignment:
Page 101
Problem 14
Five-Minute Assignment:
Element
Atomic
Number
Mass
Number
Ca 20 46
O 8 17
Fe 26 57
Zn 30 64
Hg 80 204
Protons
Electrons
Neutrons
Calculating Atomic Mass
Calculating Atomic Mass
For each isotope of an element,
multiply mass × abundance and
then add them.
Calculating Atomic Mass
For each isotope of an element,
multiply mass × abundance and
then add them.
unknown element
X
Calculating Atomic Mass
For each isotope of an element,
multiply mass × abundance and
then add them.
6
X
7
X
Calculating Atomic Mass
For each isotope of an element,
multiply mass × abundance and
then add them.
6
mass
X
6.015 amu
7
X
7.016 amu
Calculating Atomic Mass
For each isotope of an element,
multiply mass × abundance and
then add them.
6
mass
abundance
X
6.015 amu
7.50%
7
X
7.016 amu
92.5%
Calculating Atomic Mass
For each isotope of an element,
multiply mass × abundance and
then add them.
6
mass
abundance
X
6.015 amu
x 7.50%
7
X
7.016 amu
x 92.5%
Calculating Atomic Mass
For each isotope of an element,
multiply mass × abundance and
then add them.
6
mass
abundance
X
6.015 amu
x 7.50%
0.451 amu
7
X
7.016 amu
x 92.5%
6.490 amu
Calculating Atomic Mass
For each isotope of an element,
multiply mass × abundance and
then add them.
6
mass
abundance
X
7
X
6.015 amu
7.016 amu
x 7.50%
x 92.5%
0.451 amu + 6.490 amu =
Calculating Atomic Mass
For each isotope of an element,
multiply mass × abundance and
then add them.
6
mass
abundance
X
7
X
6.015 amu
7.016 amu
x 7.50%
x 92.5%
0.451 amu + 6.490 amu = 6.941
Calculating Atomic Mass
unknown
?
X
6.941
Calculating Atomic Mass
Lithium
3
Li
6.941
Homework
Page 104, problems 15-21
.
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