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)

Foiled again

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

Atoms vs. IonsAtoms are NEUTRAL!!!!!

This means that they have zero charge#p+ = #e-

My Atom Broke

Subatomic ParticlesNucleus

Neutrons – no

No charge# can vary from atom to atom

16p+

16no16p+

17no

16p+

18no16p+

20no

16p+

16no16p+

17no

16p+

18no16p+

20no

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 + +