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

The history of the periodic table http://www.youtube.com/watch?v=O-48znAg7VE&list=PLA97087254E575992

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 (35.470+126.470)/2=80.470. 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, 301-7 (1829)

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

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

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)

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)

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, 405-406 (1869)

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

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

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

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

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, 405-406 (1869)

?=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, 405-406 (1869)

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

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

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