The History of the Modern Periodic Table

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Transcript The History of the Modern Periodic Table

How to Organize Elements…
Periodic Table Designs
How to Organize…
Baseball Cards:
year, team, player, card number, value ($).
Elements:
when they weremass,
discovered,
family, reactivity,
alphabetically,
value, density,
state or
of liquid
matter,ormetal
solid
gas vs. non-metal, atomic mass,
atomic number.
Which way is CORRECT to organize the elements?
Is it possible to organize the elements correctly in more than one way?
Periodic Table
Alkali earth metals
H
1
2
3
4
5
6
7
8A
He
Alkali metals
1A
Transition metals
3A 4A 5A 6A 7A
B C N O F
1
2A
Boron group
Li
Be
Nonmetals
3
4
Na
Mg
11
12
K
Ca
19
20
21
22
Rb
Sr
Y
Zr Nb Mo Tc Ru Rh Pd Ag Cd
In
37
38
39
40
41
42
49
Cs
Ba
Hf
Ta
W
55
56
72
73
74
Fr
Ra
87
88
Noble gases
5
Al
8B
3B 4B 5B 6B 7B
1B 2B
Sc Ti V Cr Mn Fe Co Ni Cu Zn
23
24
25
26
43
27
44
Re Os
75
76
28
29
30
47
13
45
46
48
Ir
Pt Au Hg
Tl
77
78
81
79
80
7
8
9
10
Si
P
S
Cl
Ar
14
15
16
17
18
As Se Br
Kr
33
32
Sn Sb
50
51
Pb Bi
82
83
34
35
36
Te
I
Xe
52
53
54
At
Rn
85
86
Po
84
Rf Db Sg Bh Hs Mt
104
105
106
107
108
109
Lanthanoid Series
6
C
Br Liquid
H
La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
57
Solid
58
59
60
61
62
63
64
65
66
67
68
69
70
71
Actinoid Series
7
Ac Th Pa
U
Np Pu Am Cm Bk Cf
Es Fm Md No Lr
Gas
89
90
91
92
93
94
95
96
97
98
99
Ne
6
Ga Ge
31
2
100
101
102
103
Dutch Periodic Table
117
116
115
114
113
112
111
110
109
108
107
106
Strong, Journal of Chemical Education, Sept. 1989, page 743
118
Stowe’s Periodic Table
Benfey’s Periodic Table
The History of
the Modern
Periodic Table
During the nineteenth century,
chemists began to categorize the
elements according to similarities
in their physical and chemical
properties. The end result of
these studies was our modern
periodic table.
Johann Dobereiner
In 1829, he classified some elements into
groups of three, which he called triads.
The elements in a triad had similar
chemical properties and orderly physical
properties.
(ex. Cl, Br, I and
Ca, Sr, Ba)
Model of triads
1780 - 1849
Döbereiner’s Triads
Johann Döbereiner
~1817
Name
Atomic
Mass
Name
Atomic
Mass
Name
Atomic
Mass
Calcium
Barium
40
137
Chlorine
Iodine
35.5
127
Sulfur
Tellurium
32
127.5
Average
88.5
Average
81.3
Average
79.8
Strontium
87.6
Bromine
79.9
Selenium
79.2
Döbereiner discovered groups of three related elements which he termed a triad.
Smoot, Price, Smith, Chemistry A Modern Course 1987, page 161
John Newlands
In 1863, he suggested that elements be
arranged in “octaves” because he noticed
(after arranging the elements in order of
increasing atomic mass) that certain
properties repeated every 8th element.
Law of Octaves
1838 - 1898
Newlands Law of Octaves
John Newlands
~1863
Newlands Law of Octaves
1
2
3
4
5
6
7
Li
Na
K
Be
Mg
B
Al
C
Si
N
P
O
S
F
Cl
Smoot, Price, Smith, Chemistry A Modern Course 1987, page 161
John Newlands
Newlands' claim to see a repeating pattern was met
with savage ridicule on its announcement. His
classification of the elements, he was told, was as
arbitrary as putting them in alphabetical order and
his paper was rejected for publication by the
Chemical Society.
1838 - 1898
Law of Octaves
Dmitri Mendeleev
In 1869 he published a table of
the elements organized by
increasing atomic mass.
1834 - 1907
Lothar Meyer
At the same time, he published his own
table of the elements organized by
increasing atomic mass.
1830 - 1895
Elements known at this time
• Both Mendeleev and Meyer arranged
the elements in order of increasing
atomic mass.
• Both left vacant spaces where unknown
elements should fit.
So why is Mendeleev called the “father
of the modern periodic table” and not
Meyer, or both?
Mendeleev...
• stated that if the atomic weight of an
element caused it to be placed in the
wrong group, then the weight must be
wrong. (He corrected the atomic
masses of Be, In, and U)
• was so confident in his table that he
used it to predict the physical
properties of three elements that were
yet unknown.
After the discovery of these unknown
elements between 1874 and 1885, and the
fact that Mendeleev’s predictions for Sc,
Ga, and Ge were amazingly close to the
actual values, his table was generally
accepted.
However, in spite of Mendeleev’s great
achievement, problems arose when new
elements were discovered and more
accurate atomic weights determined. By
looking at our modern periodic table, can
you identify what problems might have
caused chemists a headache?
Ar and K
Co and Ni
Te and I
Th and Pa
Development of Periodic Table
J.W. Döbereiner (1829)
Law of Triads
Elements could be classified into groups of three, or triads.
Trends in physical properties such as density, melting point,
and atomic mass were observed.
J.A.R. Newlands (1864)
Law of Octaves
Arranged the 62 known elements into groups of seven
according to increasing atomic mass.
He proposed that an eighth element would then repeat the
properties of the first element in the previous group.
Lothar Meyer (1830 – 1895)
Invented periodic table independently of Mendeleev
his work was not published until 1870 - one year after Mendeleev's
Dmitri Mendeleev
• Russian
• Invented periodic table
• Organized elements by
properties
• Arranged elements by atomic
mass
• Predicted existence of several
unknown elements
• Element 101
Dmitri Mendeleev
Dmitri Mendeléev
Mendeleev’s Periodic Table
Group I
II
III
IV
V
VI
VII
VIII
F = 19
Period
1
H=1
2
Li = 7
Be= 9.4
B = 11
C = 12
N = 14
O = 16
F = 19
3
Na = 23
Mg = 24
Al = 27.3
Si = 28
P = 31
S = 32
C = 35.5
4
K = 39
Ca = 40
? = 44
Ti = 48
V = 51
Cr = 52
Mn = 55
5
Cu = 63
Zn = 65
? = 68
? = 72
As = 75
Se = 78
Br = 80
6
Rb = 85
Sr = 87
? Yt = 88
Zr = 90
Nb = 94
Mo = 96
? = 100
7
Ag = 108
Cd = 112
In = 113
Sn = 118
Sb = 122
Te = 125
J = 127
8
Cs = 133
Ba = 137
?Di = 138
?Ce = 140
?Er = 178
?La = 180
Ta = 182
W = 184
Tl = 204
Pb = 207
Bi = 208
Fe =56, Co = 59,
Ni = 59
Ru= 104, Rh = 104,
Pd = 106
9
10
11
12
Au = 199
Hg = 200
Th = 231
U = 240
Os = 195, Ir = 197,
Pt = 198
Mendeleev’s Early Periodic Table
REIHEN
TABELLE II
GRUPPE I
___
Li = 7
K = 39
11
12
RH3
R2O5
Cs = 133
Sr = 87
GRUPPE VI
GRUPPE VII
RH2
RO3
In = 113
? Di = 138
__
__
(Au = 199)
__
? Yt = 88
Ba = 137
__
Si = 28
RH
R2O7
? Er = 178
Tl= 204
__
V = 51
Zr = 90
GRUPPE VIII
___
RO4
Cr = 52
Nb = 94
? Ce = 140
From Annalen der Chemie und Pharmacie, VIII, Supplementary Volume for 1872, p. 151.
__
W = 184
Pd = 106, Ag = 108
__ __ __ __
__
__
__
U = 240
Ni = 59, Cu = 63
Ru = 104, Rh = 104,
J = 127
__
Bi = 208
__
__ = 100
__
Ta = 182
Fe = 56, Co = 59,
Br = 80
Te = 125
__
Pb = 207
Mn = 55
Mo = 96
__
Cl = 35.5
Se = 78
Sb = 122
__
? La = 180
F = 19
S = 32
As = 75
Sn = 118
Th = 231
O = 16
P = 31
? = 72
__
__
Hg = 200
N = 14
Ti = 48
? = 68
__
Cd = 112
( __ )
__
Al = 27.3
Zn = 65
(Ag = 108)
C = 12
? = 44
__
Ca = 40
Rb = 85
9
10
GRUPPE V
RH4
RO2
B = 11
Mg = 24
(Cu = 63)
7
8
Be = 9.4
Na = 23
5
6
RO
R2O3
GRUPPE IV
H=1
3
4
GRUPPE III
___
R2O
1
2
GRUPPE II
___
Os = 195, Ir = 197,
__
__
Pt = 198, Au = 199
__ __ __ __
Elements Properties are Predicted
Property
Mendeleev’s Predictions in 1871
Observed Properties
Scandium (Discovered in 1877)
Molar Mass
Oxide formula
Density of oxide
Solubility of oxide
44 g
M2O3
3.5 g / ml
Dissolves in acids
43.7 g
Sc2O3
3.86 g / ml
Dissolves in acids
Gallium (Discovered in 1875)
Molar mass
Density of metal
Melting temperature
Oxide formula
Solubility of oxide
68 g
6.0 g / ml
Low
M2O3
Dissolves in ammonia solution
69.4 g
5.96 g / ml
30 0C
Ga2O3
Dissolves in ammonia
Germanium (Discovered in 1886)
Molar mass
Density of metal
Color of metal
Melting temperature
Oxide formula
Density of oxide
Chloride formula
Density of chloride
Boiling temperature
of chloride
72 g
5.5 g / ml
Dark gray
High
MO2
4.7 g / ml
MCl4
1.9 g / ml
Below 100 oC
O’Connor Davis, MacNab, McClellan, CHEMISTRY Experiments and Principles 1982, page 119,
71.9 g
5.47 g / ml
Grayish, white
900 0C
GeO2
4.70 g / ml
GeCl4
1.89 g / ml
86 0C
1
H
Periodic Table of the
Elements
He
1
2
3
Li
Be
B
C
N
O
F
Ne
3
4
5
6
7
8
9
10
Al
Si
P
S
Cl
Ar
13
14
15
16
17
18
Na Mg
11
4
K
19
5
7
12
Ca Sc
Ti
V
Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br
Kr
23
24
35
36
I
Xe
53
54
20
21
22
Rb Sr
Y
Zr Nb Mo Tc Ru Rh Pd Ag Cd
In
39
40
41
42
49
Hf
Ta
W
72
73
74
37
6
2
38
Cs Ba
55
56
Fr
Ra
87
88
*
W
25
43
26
44
Re Os
75
76
27
28
29
47
30
45
46
Ir
Pt Au Hg
Tl
77
78
81
79
48
31
80
32
33
34
Sn Sb Te
50
51
Pb Bi
82
83
52
Po At Rn
84
85
86
Rf Db Sg Bh Hs Mt
104
105
106
107
108
109
La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
57
58
59
Ac Th Pa
89
90
91
60
U
92
61
62
63
64
65
66
Np Pu Am Cm Bk Cf
93
94
95
96
97
98
67
68
69
70
71
Es Fm Md No Lr
99
100
101
102
103
Henry Moseley
In 1913, through his work with X-rays, he
determined the actual nuclear charge
(atomic number) of the elements*. He
rearranged the elements in order of
increasing atomic number.
*“There is in the atom a fundamental
quantity which increases by regular
steps as we pass from each element to
the next. This quantity can only be the
charge on the central positive nucleus.”
1887 - 1915
Henry Moseley
His research was halted when the British
government sent him to serve as a foot
soldier in WWI. He was killed in the
fighting in Gallipoli by a sniper’s bullet, at
the age of 28. Because of this loss, the
British government later restricted its
scientists to noncombatant duties during
WWII.
Modern Periodic Table
• Henry G.J. Moseley
• Determined the atomic
numbers of elements
from their X-ray spectra
(1914)
• Arranged elements by
increasing atomic number
• Killed in WW I at age 28
(Battle of Gallipoli in Turkey)
1887 - 1915
Glenn T. Seaborg
After co-discovering 10 new elements, in
1944 he moved 14 elements out of the
main body of the periodic table to their
current location below the Lanthanide
series. These became known
as the Actinide series.
1912 - 1999
Glenn T. Seaborg
He is the only person to have an element
named after him while still alive.
"This is the greatest honor ever bestowed
upon me - even better, I think, than
winning the Nobel Prize."
1912 - 1999