1. Física y química 3º E.S.O.
FIRST TERM
UNIT 2_1:
CHEMICAL SUBSTANCES

2. The history of the periodic table

3. THE TRIAD MODEL (1829)
Johann Wolfgang Döbereiner
In 1829, he observed that elements with similar physical and chemical properties fall into groups of three. He called these related groups of three elements triads.
In each of these triads, the atomic weight of the intermediate element is approximately the average of the atomic weights of the other two elements
( )/2=
Iodine
Chlorine
Bromine
ELEMENT
Atomic
mass
35,470
126,470
78,383
Other triads proposed by Döbereiner are …
Ca-Sr-Ba
S-Se-Te
Li-Na-K
Un intento de agrupar sustancias elementales de acuerdo con sus analogías
Poggendorf´s Annalen der Physik und Chemie 15, (1829)

4. TELURIC HELIX (1862)
Alexandre-Emile Béguyer de Chancourtois
De Chancourtois devised a spiral graph that was arranged on a cylinder which he called vis tellurique, or telluric helix because tellurium was the element in the middle of the graph

5. TELURIC HELIX (1862)
Alexandre-Emile Béguyer de Chancourtois 2 4 8 6 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56
* Li
* H
* Be
* B
* C
* N
* O * GI Bo Az
* S
* P
* Si
* Al
* Mg
* Na
* NH4 Ph
* V
* Ti
* Ca
* K
* Cl
* Fe
* Cr
De Chancourtois ordered the elements by increasing atomic weight and with similar elements lined up vertically
*Be
*Mg
*Ca
Li*
Na* K*
Elements with similar characteristics
Elements with similar characteristics

6. THE LAW OF OCTAVES (1865)
John A.R. Newlands
In 1864, an English chemist, John Newlands, arranged the known elements in increasing order of their atomic weights. He noted that chemically similar elements occurred every eight elements
No.
H 1
F 8
Cl 15
Co&Ni 22
Br 29
Pd 36
I 42
Pt&Ir 50
Li 2
Na 9
K 16
Cu 23
Rb 30
Ag 37
Cs 44
Os 51
G 3
Mg 10
Ca 17
Zn 25
Sr 31
Cd 38
Ba&V 45
Hg 52
Bo 4
Al 11
Cr 19
Y 24
Ce&La 33
U 40
Ta 46
Tl 53
C 5
Si 12
Ti 18
In 26
Zr 32
Sn 39
W 47
Pb 54
N 6
P 13
Mn 20
As 27
Di&Mo 34
Sb 41
Nb 48
Bi 55
O 7
S 14
Fe 21
Se 28
Ro&Ru 35
Te 43
Au 49
Th 56
Lighter sodium was like potassium, and so on through pairs of elements until fluorine and chlorine, the seventh pair
About the law of octaves
Chemical News, 12, 83 (1865)

7. John A.R. Newlands
LEY DE OCTAVAS
(1865)
Newlands called the repeating pattern the Law of Octaves since the eighth element resembled the first.
No.
H 1
F 8
Cl 15
Co&Ni 22
Br 29
Pd 36
I 42
Pt&Ir 50
Li 2
Na 9
K 16
Cu 23
Rb 30
Ag 37
Cs 44
Os 51
G 3
Mg 10
Ca 17
Zn 25
Sr 31
Cd 38
Ba&V 45
Hg 52
Bo 4
Al 11
Cr 19
Y 24
Ce&La 33
U 40
Ta 46
Tl 53
C 5
Si 12
Ti 18
In 26
Zr 32
Sn 39
W 47
Pb 54
N 6
P 13
Mn 20
As 27
Di&Mo 34
Sb 41
Nb 48
Bi 55
O 7
S 14
Fe 21
Se 28
Ro&Ru 35
Te 43
Au 49
Th 56 Do Do Re Mi Fa
Sol La Si
Sobre la ley de octavas
Chemical News, 12, p. 83 (1865)

8. THE PERIODIC LAW (1869)
Dimitri Mendeleiev
In the mid-1800s, most chemists worldwide were convinced that the elements existed in families that had similar physical and chemical properties
In Principles of Chemistry, published in 1869, Mendeleev introduced a concept he called the Periodic Law that stated:
The properties of the elements are a periodic function of their atomic weights.
Sobre la relación de las propiedades de los elementos con sus pesos atómicos
D. Mendelejeff, Zeitscrift für Chemie, 12, (1869)

9. THE PERIODIC LAW (1869)
Dimitri Mendeleiev
How was Mendeleev able to chart the relationships among the 63 known elements?
It all started in a game of cards
Mendeleev developed a card game. He wrote out the properties of each element on a different card and spent a great deal of time arranging and rearranging them. He was looking for patterns or trends in the data on the cards. His friends called this game “Patience.”
Mendeleev first arranged all the cards from lowest to highest atomic mass

10. The second lightest element known to Mendeleev was lithium
Mendeleev first arranged all the cards from lowest to highest atomic mass
Cr=52
Ti=50
Fe=56
Mn=55
Ni=Co=59
Cu=63,4
Zn=65,2
?=68
?=70
Se=79,4
Br=80
Rb=85,4
Sr=87,6
Ce=92
La=94
Th=118?
V=51
As=75
Di=95
Mo=96
Zr=90
Ru=104,4
Rh=104,4
Pd=106,6
Ag=108
Cd=112
Ur=116,6
Sn=118
Te=128?
I=127
Cs=133
Ba=137
Nb=94
Sb=112
W=186
?=180
Ir=198
Pt=197,4
Os=199
Hg=200
Au=197?
Tl=204
Pb=207
Ta=182
Bi=210?
Mg=24
Al=27,4
Si=28
S=32
Cl=35,5
K=39
Ca=40
?=45
?Er=56
?In=75,6
P=31
?Yt=95
Be=9,4
B=11
C=12
O=16
F=19
Na=23
N=14
H=1
Li=7
The lightest element known in Mendeleev’s time was hydrogen
The second lightest element known to Mendeleev was lithium

11. Mendeleev first arranged all the cards from lowest to highest atomic mass
Cr=52
Ti=50
Fe=56
Mn=55
Ni=Co=59
Cu=63,4
Zn=65,2
?=68
?=70
Se=79,4
Br=80
Rb=85,4
Sr=87,6
Ce=92
La=94
Th=118?
V=51
As=75
Di=95
Mo=96
Zr=90
Ru=104,4
Rh=104,4
Pd=106,6
Ag=108
Cd=112
Ur=116,6
Sn=118
Te=128?
I=127
Cs=133
Ba=137
Nb=94
Sb=112
W=186
?=180
Ir=198
Pt=197,4
Os=199
Hg=200
Au=197?
Tl=204
Pb=207
Ta=182
Bi=210?
Mg=24
Al=27,4
Si=28
S=32
Cl=35,5
K=39
Ca=40
?=45
?Er=56
?In=75,6
P=31
?Yt=95
Be=9,4
B=11
C=12
O=16
F=19
Na=23
N=14
H=1
Li=7
Beryllium, boron, carbon, nitrogen, oxygen, and fluorine were all different in their physical and chemical properties, thus seeming to belong to different families. Mendeleev put their cards in a vertical row, with lithium at the top and fluorine at the bottom

12. Mendeleev first arranged all the cards from lowest to highest atomic mass
Cr=52
Ti=50
Fe=56
Mn=55
Ni=Co=59
Cu=63,4
Zn=65,2
?=68
?=70
Se=79,4
Br=80
Rb=85,4
Sr=87,6
Ce=92
La=94
Th=118?
V=51
As=75
Di=95
Mo=96
Zr=90
Ru=104,4
Rh=104,4
Pd=106,6
Ag=108
Cd=112
Ur=116,6
Sn=118
Te=128?
I=127
Cs=133
Ba=137
Nb=94
Sb=112
W=186
?=180
Ir=198
Pt=197,4
Os=199
Hg=200
Au=197?
Tl=204
Pb=207
Ta=182
Bi=210?
Mg=24
Al=27,4
Si=28
S=32
Cl=35,5
K=39
Ca=40
?=45
?Er=56
?In=75,6
P=31
?Yt=95
Be=9,4
B=11
C=12
O=16
F=19
Na=23
N=14
H=1
Li=7
Mendeleev was thinking about the similar properties of the next elements.
Magnesium, following sodium, had physical and chemical properties similar to beryllium, which followed lithium. In the same manner, Mendeleev placed aluminum next to boron; silicon next to carbon; phosphorus next to nitrogen; sulfur next to oxygen; and chlorine next to fluorine

13. Br=80 I=127 Cl=35,5 F=19 Dimitri Mendeleiev THE PERIODIC LAW (1869)
Cr=52
Ti=50
Fe=56
Mn=55
Ni=Co=59
Cu=63,4
Zn=65,2
?=68
?=70
Se=79,4
Br=80
Rb=85,4
Sr=87,6
Ce=92
La=94
Th=118?
V=51
As=75
Di=95
Mo=96
Zr=90
Ru=104,4
Rh=104,4
Pd=106,6
Ag=108
Cd=112
Ur=116,6
Sn=118
Te=128?
I=127
Cs=133
Ba=137
Nb=94
Sb=112
W=186
?=180
Ir=198
Pt=197,4
Os=199
Hg=200
Au=197?
Tl=204
Pb=207
Ta=182
Bi=210?
Mg=24
Al=27,4
Si=28
S=32
Cl=35,5
K=39
Ca=40
?=45
?Er=56
?In=75,6
P=31
?Yt=95
Be=9,4
B=11
C=12
O=16
F=19
Na=23
N=14
H=1
Li=7
Dimitri Mendeleiev
THE PERIODIC LAW
(1869)
“Elements in the same row show similar properties”
Sobre la relación de las propiedades de los elementos con sus pesos atómicos
D. Mendelejeff, Zeitscrift für Chemie, 12, (1869)

14. ?=68 ?=70 Dimitri Mendeleiev LEY PERIÓDICA (1869)
Cr=52
Ti=50
Fe=56
Mn=55
Ni=Co=59
Cu=63,4
Zn=65,2
?=68
?=70
Se=79,4
Br=80
Rb=85,4
Sr=87,6
Ce=92
La=94
Th=118?
V=51
As=75
Di=95
Mo=96
Zr=90
Ru=104,4
Rh=104,4
Pd=106,6
Ag=108
Cd=112
Ur=116,6
Sn=118
Te=128?
I=127
Cs=133
Ba=137
Nb=94
Sb=112
W=186
?=180
Ir=198
Pt=197,4
Os=199
Hg=200
Au=197?
Tl=204
Pb=207
Ta=182
Bi=210?
Mg=24
Al=27,4
Si=28
S=32
Cl=35,5
K=39
Ca=40
?=45
?Er=56
?In=75,6
P=31
?Yt=95
Be=9,4
B=11
C=12
O=16
F=19
Na=23
N=14
H=1
Li=7
Dimitri Mendeleiev
LEY PERIÓDICA
(1869)
Mendeleev not only suggested that elements similar to aluminum and silicon should exist. He predicted several properties of "ekasilicon.“
This element was found. It was called Germanium
Sobre la relación de las propiedades de los elementos con sus pesos atómicos
D. Mendelejeff, Zeitscrift für Chemie, 12, (1869)

15. Dimitri Mendeleiev
Mendeleev became world famous because of his development of the periodic table of the elements.
Mendeleev was honored posthumously in 1955 when Mendelevium, manmade element number 101 in the modern periodic table, was named for him.
Mendelevium

16. The periodic law was not perfect
Cr=52
Ti=50
Fe=56
Mn=55
Ni=Co=59
Cu=63,4
Zn=65,2
?=68
?=70
Se=79,4
Br=80
Rb=85,4
Sr=87,6
Ce=92
La=94
Th=118?
V=51
As=75
Di=95
Mo=96
Zr=90
Ru=104,4
Rh=104,4
Pd=106,6
Ag=108
Cd=112
Ur=116,6
Sn=118
Te=128?
I=127
Cs=133
Ba=137
Nb=94
Sb=112
W=186
?=180
Ir=198
Pt=197,4
Os=199
Hg=200
Au=197?
Tl=204
Pb=207
Ta=182
Bi=210?
Mg=24
Al=27,4
Si=28
S=32
Cl=35,5
K=39
Ca=40
?=45
?Er=56
?In=75,6
P=31
?Yt=95
Be=9,4
B=11
C=12
O=16
F=19
Na=23
N=14
H=1
Li=7
Dimitri Mendeleiev
THE PERIODIC LAW
(1869)
The periodic law was not perfect
Some elements did not follow the periodic law
Iodine has a lower relative atomic mass than tellurium
In order to get iodine in the same group as other elements with similar properties such as fluorine, chlorine and bromine, he had to put it after tellurium, so breaking his own rules

17. This solved the anomalies found for the Mendeleev´s periodic law
Henry Moseley in 1913, proposed to use the atomic number instead of atomic mass as the organising principle
This solved the anomalies found for the Mendeleev´s periodic law
Atomic number = Number of protons