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25th Amendment is Ratified (1967) Reading for Thursday: Chapter 5 sections 6-11 Homework 4 – Due Thursday 2/12/15
Chapter 4 #'s 2-22 (even), 28, 30, 35, 36, 38, 40, 44, 46, 52, 54, 59, 60, 66 (only assignment from chapter 4)
Homework 5 – Due Tuesday 2/17/15 Chapter 5 #'s 18, 20, 22, 34, 36, 39-46 (all), 55, 56, 61, 62, 70, 72, 94
(only assignment from chapter 5)
The Atom
REALLY early atomic theory…Democritus ~350 BCAtomos - Greek meaning indivisible
Modern Definition: Smallest piece that matter can be broken up
into and still maintain the properties of an element
My Atom Broke
Subatomic ParticlesNucleus
Protons – p+
Carry a single positive chargeNumber of p+ = ATOMIC NUMBER
1H
1.013Li6.9411Na22.9919K
39.1037Rb85.4755Cs
132.9187Fr
(223)
4Be9.0112Mg24.3120Ca40.0838Sr
87.6256Ba
137.3388Ra(226)
21Sc
44.9639Y
88.9157La
138.9189Ac(227)
22Ti
47.8840Zr
91.2272Hf
178.49104Rf
(261)
23V
50.9441Nb92.9173Ta
180.95
24Cr52.0042Mo95.9474W
183.85
25Mn54.9443Tc(99)75Re
186.21
26Fe
55.8544Ru
101.0776Os190.2
27Co58.9345Rh
102.9177Ir
192.22
28Ni
58.6946Pd
106.4278Pt
195.08
29Cu63.5547Ag
107.8779Au
196.97
30Zn65.3948Cd
112.4180Hg
200.59
5B
10.8113Al
26.9831Ga69.7249In
114.8281Tl
204.38
6C
12.0114Si
28.0932Ge72.6150Sn
118.7182Pb207.2
7N
14.0115P
30.9733As
74.9251Sb
121.7583Bi
208.98
8O
16.0016S
32.0734Se
78.9652Te
127.6084Po(209)
9F
19.0017Cl
35.4535Br
79.9053I
126.90
10Ne20.1818Ar39.9536Kr83.8054Xe
131.29
2He4.00
58Ce
140.12
59Pr
140.91
60Nd
144.24
61Pm(147)
62Sm
150.36
63Eu
151.97
64Gd
157.25
65Tb
158.93
66Dy
162.50
67Ho
164.93
68Er
167.26
69Tm168.93
70Yb
173.04
71Lu
174.97
85At
(210)
86Rn(222)
90Th(232)
91Pa(231)
92U
(238)
93Np(237)
94Pu(244)
95Am(243)
96Cm(247)
97Bk(247)
98Cf
(251)
99Es
(252)
100Fm(257)
101Md(258)
102No(259)
103Lr(260)
105Db(262)
106Sg
(263)
107Bh(262)
108Hs(265)
109Mt(266)
110Ds(271)
111Rg(272)
112--
(277)
114--
(285)
116--
(289)
1IA
2IIA
3IIIB
4IVB
5VB
6VIB
7VIIB
8VIII
9VIII
10VIII
11IB
12IIB
13IIIA
14IVA
15VA
16VIA
17VIIA
18VIIIA
My Atom BrokeSubatomic Particles
NucleusNeutrons – no
No charge# can vary from atom to atom
Roughly the same size as p+
My Atom Broke
Subatomic ParticlesOutside the nucleus
Electrons – e-
negative charge1/1900th the size of p+ and no
Responsible for most of the chemistry that ever happens
16p+
20no
16p+
18no
16p+
17no
16p+
16no
Mass of no about equal to mass of p+
Do each of these atoms have the same mass?
Isotopes: Atoms having the same atomic number, but different atomic masses
Atom notation
EA
Z
Symbol of
element
Atomic number
Mass number= # p+ + # no
S16
16p+
20no
16p+
18no
16p+
17no
16p+
16no
32
16
16p+
20no
16p+
18no
16p+
17no
16p+
16noA
Z
S
E32
16S
33
16S
34
16S
36
16S
Shorthand: Sulfur-33
S-3636S
Give the atom notation for the following:
1) an atom with 82 p+ and 126 no
2) an atom of iron with 28 no
3) an atom of element 29 having 34 no
208
82Pb
54
26Fe
63
29Cu
82 p+ + 126 no =
24Cr53
Atomic Notation
Atomic Number
Mass Number
Number of p+
Number of no
Number of e-
8383Bi209 126 83209 83
74 535353 12753I127
24 53 24 29 24
Name that Isotope
Hydrogen has 3 isotopes
hydrogen-1 has zero no
hydrogen-2 has 1 no
hydrogen-3 has 2 no
1H2H or D or deuterium3H or T or tritium
Information from the Periodic Table
= 40.08 amu (atomic mass)
= 16.00 amu (atomic mass)
(atomic number) 20 =
(atomic number) 8 =
20Ca40.08
8O
16.00
Atomic MassesMeasured in the unit amu
Stands for atomic mass unitDefined as 1/12th the mass of a 12C atom
35Cl = 34.9689 amu 50V = 49.9472 amu 79Br = 78.9183 amuAre these what the P.T. say?
All Isotopes are NOT Created EqualWeighted averages
“Normal averages” assume that everything counts the same.
Splitting the dinner bill assuming everyone ate and drank the same amount
Weighted averages take into account the fact that everything does NOT count the same.
Making my brother pay a larger part of the dinner bill because he ate more.
All Isotopes are NOT Created EqualWeighted averagesAn equation (oh crap)
35Cl = 34.9689 amuAbundance = 75.77%
37Cl = 36.9659 amuAbundance = 24.23%
These must be the only 2 isotopes... Why?
isotope mass 1 abundance 1 isotope mass 2 abundance 2 average atomic mass
35Cl = 34.9689 amuAbundance = 75.77%
37Cl = 36.9659 amuAbundance = 24.23%
isotope mass 1 abundance 1 isotope mass 2 abundance 2 average atomic mass
34.9689x 0.7577+ 36.9659 x 0.2423 = 35.45amu
Where have I seen this before?
Periodic Table gives AVERAGE ATOMIC MASS in amu!!
=0.7577
=0.2423
All Isotopes are NOT Created Equal
isotope mass 1 abundance 1 isotope mass 2 abundance 2 average atomic mass+
78.90% of all magnesium is 24Mg 23.985 amu
10.00% of all magnesium is 25Mg 24.986 amu
11.10% of all magnesium is 26Mg 25.983 amu11.10%
100.00%23.985 0.7890 18.92
24.986 0.1000 2.499
25.983 0.1110 2.884
24.303
= 24.30 amu
A Problem!What is the average atomic mass of magnesium?
Another Problem!Lead has 4 isotopes, the masses and abundances of which can be found in the following table. Your job? Calculate the isotope mass of lead-207.
lead-204 203.973 amu 1.40%
lead-206 205.974 amu 24.10%
lead-207 ????
lead-208 207.977 amu 52.40%
????22.10%
X = Lead-207 = 206.9 amu
isotope mass 1 abundance 1 isotope mass 2 abundance 2
isotope mass 3 abundance 3 isotope mass 4 abundance 4 average atomic mass
+
+
203.973 0.0140 205.974 0.2410 X 0.2210 207.977 0.5240 207.2 + +