A. SCIENTIST NOTES – Discovering the atom-15-16 skip this page
NAME
CONTRIBUTION/EXPERIMENT
http://www.youtube.com/watch?v=Rb6MguN0Uj4
JOHN DALTON
The above video includes Thomson
J. J. THOMSON
http://www.youtube.com/watch?v=dNp-vP17asI
ERNEST
RUTHERFORD
NIELS BOHR
https://www.youtube.com/watch?v=GhAn8xZQ-d8
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MODEL
http://www.pbslearningmedia.org/resource/lsps07.sci.phys.matter.theatom/the-atom/
Amu = atomic mass unit
ATOMIC STRUCTURE - http://youtu.be/-0xxEWd9utc just watch 2 min
PARTICLE
LOCATION
CHARGE
1 amu = 1/12 mass of _____ atom
RELATIVE MASS
proton
________amu
neutron
________amu
electron
________amu
http://youtu.be/o-3I1JGW-Ck
atom – the smallest part of an element that_________________________________________________________
http://youtu.be/dRfrvpVdKGM
An atom is __________________________(no net charge,) which means that
the # of protons (p+) = # of electrons (e-)
Periodic Table “Box”
Isotopic Notation http://youtu.be/BYiu0kIWd30
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Na
22.9897
atomic number –___________________________________________________________________________
mass number ___________________________________________________________________________
2
Look up the atomic number on the periodic table and add it to the bottom of the isotopic notation.
For Sodium
23
For Oxygen
16
For fluorine
For Sodium
Na
______p+
_______#e-
O
______p+
_______#e-
_________n0
19
F
______p+
_______#e-
_________n0
22
Na
______p+
_______#e-
_________n0
_________n0
http://youtu.be/EboWeWmh5Pg
example #1
The average
atomic mass
for C is
____________
Isotopes - ________________________________________________________________________________
They have the same #________ but different number of _______________.
example #2
The average
atomic mass for
Li is (use periodic
table)
____________
example #3
The average
atomic mass for
Cl is
____________
3
http://youtu.be/m15DWkkGe_0
Do you see mass numbers or Average Atomic Mass (Average Atomic Weight) on the
periodic table?_________________ ____________________________________
http://youtu.be/n4WZ0-fItt8
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PRACTICE: ISOTOPES AND AVERAGE ATOMIC MASS
Determine the average atomic mass of the following isotopes:
1. 80.0% 127I,
2. 50.0% 197Au,
3. 15.0% 55Fe,
17.0% 126I,
3.00% 128I
50.0% 198Au
85.0% 56Fe
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4. 99.0% 1H,
0.800% 2H,
0.200% 3H
5. 95.0% 14N,
3.00% 15N,
2.00% 16N
6. 98.0% 12C,
2.00% 14C
Magnesium has 3 isotopes:
23Mg
Use: Detailed (if given)
(Mg-23)……….23.020amu
Relative abundance
0.500 %
24Mg
(Mg-24)………..24.012amu
79.5 %
25Mg
(Mg-25)………..24.997amu
20.0 %
5. CHALLENGE
a. Chlorine exists in nature as Cl-35 (atomic mass of 34.969 amu)
and Cl-37 (atomic mass of 36.966 amu). Since the atomic mass of chlorine is 35.453 amu, find the
percent abundances of these 2 isotopes found in nature.
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b. Copper is made up of 2 isotopes, Cu-63 and Cu-65. Given that the atomic mass of copper from the
periodic table is 63.546, find the percent abundance of these 2 isotopes.
http://youtu.be/WWc3k2723IM
http://youtu.be/a9WrrF8esuY
Symbol
Atomic
Number
Mass
Number
# of
Protons
# of Neutrons
Mg
13
65
30
Be
Hg
# of
electrons
5
80
4
200
16
8
10
What do we call that?
_________
Class Warm-up
1. Find the element with an atomic number of 19._________
2. How many protons does that element have?_________
3. How many electrons does that element have?_________
4. Determine the # of protons and the # of electrons in one atom of calcium
(Ca).___________________________
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5. List the number of protons, neutrons, and electrons in the following atoms:
14
37
C
18
Cl
6
O
17
8
p+
______
_______
______
n
______
_______
______
e-
______
_______
______
6. Fill in the number of protons, neurons, and electrons in the following ions:
27
32
Al3+
S2-
13
16
p+
______
_______
n
______
_______
e-
______
_______
7. Fill in the following table:
(a)
Isotopic Notation
________
(b)
________
ATOMIC #
__30____
________
MASS #
________
___80___
# PROTONS
________
___35___
# NEUTRONS
__36____
________
# ELECTRONS
__28____
________
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8. C -12
is the most abundant isotope for carbon. C- 14 also exists.
What does the number following the dash represent? _________ (how do we know that it cannot be the
atomic number?____________________________________________________________
9. (ex) Mg- 27
______p+
_______#e-
10. (ex) H-- 1
(
_________n0
H-- 2
) isotopic notation
H--3
#p+ = ___
#p+ = ___
#p+ =
#e- = ___
#e- = ___
#e- =
___
#n0 = ___
#n0 = ___
#n0 =
___
___
Which choice below shows isotopes?________ Which choice is an atom and an ion?_________
Which choice is impossible?___________ Which choice is just 2 different elements?________
4
w.
2
35
He
H
y.
1
17
16
16
17
O
8
z.
O
8
Cl
17
14
C
6
7
-1
Cl
2
x.
35
C
6
Symbol
Mass #
Atomic #
# e-
#p+
#n
Isotopic
Notation
(Don’t look
up and
round. Add
up the ___
and ___)
A-3
(look up
symbol and
put mass #
and atomic #
and charge)
83
B
126
78
C
184
D
53
74
25
D
E+5
117
31
210
80
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The Mole
a. http://youtu.be/wHwGm9oL-GA
http://youtu.be/NMdN1LtHuDA
WATCH ALL 3 OF THESE VIDEOS!!!!!
http://youtu.be/HMAOrGpkTsQ
1 mole = molar
mass
MASS (g)
MOLE
(look it up on
the PT!)
1 mole =
6.02 x 1023
atoms
PARTICLES
(ATOM)
B. MOLAR MASS AND MOLE CONVERSIONS
1 mole = 6.02 x 1023 particles
and
1 mole = _____grams (molar mass found on periodic table)
Avogadro’s number: 6.02 x 1023 particles= 1 mole
6.02 x 1023 atoms = 1 mole
6.02 x 1023 molecules = 1 mole (covalent)
6.02 x 1023 formula units = 1 mole (ionic)
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Molar Mass:
the mass of of 1 mole of an element (in grams)
Molar mass of Na is 22.99 g/mol. (use Periodic table)
Molar mass of C is 12.01 g/mol. (use Periodic table)
Molar mass of He is 4.00 g/mol. (use Periodic table)
Na
22.9897
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CONVERSION FACTORS:
mole = 6.02 x 1023 atoms
1 mole = atomic mass (g)
1. How many atoms are in 6.5 moles of zinc?
6.5 moles Zn
6.02 x 1023 atoms Zn =
3.91 x 1024 atoms Zn
1 mole Zn
2. How many moles of argon are in a sample containing 2.4 x 1024 atoms of argon?
2.4 x 1024 atoms of argon
1 mole
6.02 x 1023 atoms
=
3.99 mol of argon
3. How many moles are in 2.5g of lithium?
4. Find the mass of 4.8moles of iron.
CONVERSION FACTORS:
1 mole = 6.02 x 1023 atoms
Two Step Problems:
1. What is the mass of 2.25 x 1025 atoms of lead?
2. How many atoms are in 10.0g of gold?
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1 mole = atomic mass (g)
PRACTICE PROBLEMS:
a. Convert to moles:
1. 625g of copper
2. 4.25 x 1026 atoms of barium
b. How many atoms are in:
1.
2.35 moles of carbon
2.
4.0g of potassium
3.
9500g of iron
c. Determine the mass of:
1. 0.250 moles of aluminum
2. 3.48 x 1022 atoms of tin
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3.
4.48 x 1021 atoms of magnesium - report your answer in regular and scientific notation
Try:
4. How many moles is 2.50kg of lead?
5.
Find the mass, in cg, of 3.25 x 1021 atoms of lithium
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