Periodic Table Timelines

Periodic Table Timelines:

A chronology of the events that have resulted in our present periodic table of the elements and
a celebration of the 150th anniversary of the Mendeleev (birthday, 02/08/1834) periodic table (1869). 

(Note:  A Powerpoint presentation of the historical developments that have culminated in our current periodic table is available at:
http://murov.info/timeline.pptx ).  This slide presentation contains images but minimal narrative which needs to be provided by the presenter.)
One example of a YouTube presentation on the development of the periodic table is available at:  https://www.youtube.com/watch?v=I5H1SeepnaU

A web site containing many of the important milestones in organic chemistry is available (6/10/18) at http://murov.info/organicmilestones.htm

https://cen.acs.org/articles/96/i1/Periodic-table-turns-150-2019.html
https://en.unesco.org/news/2019-proclaimed-international-year-periodic-table-chemical-elements
https://iupac.org/united-nations-proclaims-international-year-periodic-table-chemical-elements/

CONTENTS

Chronology for the development and discovery of the periodic table, atomic structure, electronic theory and the elements. 

Three thead timeline for the development of the periodic table, atomic structure and electronic theory.

Medium-long forms of the periodic table with element colors.

Selected periodic properties of the elements (ionization energy, atomic radius, valence).

Some periodic table questions and unresolved issues.

 

Chronology for the development and discovery of the periodic table, atomic structure, electronic theory and the elements. 

Image1

contributor

contribution

year

element2

Location

#3

At. #

 

 

 

 

 

 

 

 

 

 

 

>9000 BC

Copper

Mid-East

  1

29

 

 

 

  7000 BC

Lead

Egypt

  2

82

 

 

 

>6000 BC

Gold

Egypt

  3

79

 

 

 

>5000 BC

Silver

Greece

  4

47

 

 

 

>5000 BC

Iron

Egypt

  5

26

 

 

 

  3750 BC

Carbon

Egypt

  6

6

 

 

 

  3500 BC

Tin

Egypt

  7

50

 

 

 

>2000 BC

Sulfur

China

  8

16

 

 

 

>2000 BC

Mercury

China

  9

80

 

 

 

>1600 BC

Antimony

 

10

51

 

 

 

>1000 BC

Zinc

India

11

30

Image result for Empedocles

Empedocles

Proposed 4 element concept – everything derivable from earth, air, fire and water.

450 BC

 

Greece

 

 

http://static.newworldencyclopedia.org/thumb/8/8a/Leucippus.jpg/200px-Leucippus.jpg

Democritus,

Leucippus

Based on reason, as contrasted with experiment, proposed that there is a limit to the subdivision of matter that culminates in an indivisible particle called atomos.

440 BC

 

Greece

 

 

http://2.bp.blogspot.com/-5G1H2WNdPpc/VlPXpzxYe8I/AAAAAAAAH20/9k1_dJp43Lw/s1600/Lessons-%2BFrom-%2BAristotle%2B.jpg

Plato, Aristotle

Added a fifth element, "aether", promoted concept of continuity of matter and rejected concept of atoms.  As a result, atoms were not generally accepted as reality for the next 2000 years.

340 BC

 

Greece

 

 

      300 Arsenic Egypt 12 33

Related image

Jabir ibn Hayyan

Experimentalist and alchemist recognized by some as father of chemistry.  He developed classifications of metals and non-metals.

800

 

Iran, Iraq

 

 

 

Robert Boyle

 

 

Considered by many as the first modern chemist.  Author of  Sceptical Chymist.

1661

 

Ireland, England

 

 

 

Hennig  Brand

 

1669

Phosphorus

Germany

13

15

Georg Ernst Stahl

Stahl promoted the concept of phlogiston first proposed by his mentor, Johann Joachim Becher, and then expanded by Stahl’s student, J. H. Pott but debunked years later by Lavoisier and others.

1703

 

Germany

 

 

 

George Brandt

 

1735

Cobalt

Sweden

14

27

 

A. de Ulloa

 

1735

Platinum

Columbia

15

78

 

A. Cronstedt

 

1751

Nickel

Sweden

16

28

 

C. Younger

 

1753

Bismuth

France

17

83

 

Joseph Black

 

1755

Magnesium

Scotland

18

12

 

H. Cavendish

 

1766

Hydrogen

England

19

1

 

Carl Scheele,

Joseph Priestley

 

1772

Oxygen

Sweden

England

20

8

 

D. Rutherford

 

1772

Nitrogen

Scotland

21

7

 

Carl Scheele

 

1774

Chlorine

Sweden

22

17

 

Johan G. Gahn

 

1774

Manganese

Sweden

23

25

See the source image

Antoine Lavoisier

Considered to be founder of modern chemistry, demonstrated conservation of mass in chemical reactions within measureable limits, dealt phlogiston concept a blow and attempted to organize matter by properties.  Provided empirical evidence for elements as contrasted to earlier abstract concept. 

http://www.meta-synthesis.com/webbook/35_pt/pt_database.php?PT_id=3

1778

 

France

 

 

 

Carl Scheele

 

1778

Molybdenum

Sweden

24

42

 

J. & F. Elhuyar

 

1783

Tungsten

Spain

25

74

 

F.  Reichenstein

 

1783

Tellurium

Romania

26

52

 

M. H. Klaproth

 

1789

Zirconium

Germany

27

40

 

M. H. Klaproth

 

1789

Uranium

Germany

28

92

 

A. Crawford,

W.  Cruickshank

 

1790

Strontium

Scotland

29

38

 

William Gregor

 

1791

Titanium

England

30

22

 

Johann  Gadolin

 

1794

Yttrium

Finland

31

39

Jeremias B. Richter

Suggested that chemical reactions have a mathematical relationship that he called stoichiometry and proposed law of definite proportions.

1794

 

Germany

 

 

Related image

Joseph Proust

Responsible for law of constant composition.

1794

 

France

 

 

 

L-N.  Vauquelin

 

1797

Chromium

France

32

24

 

L-N.  Vauquelin

 

1798

Beryllium

France

33

4

 

A. M.  Del Rio

 

1801

Vanadium

Spain

34

23

 

C. Hatchett

 

1801

Niobium

England

35

41

 

A. G. Ekenberg

 

1802

Tantalum

Sweden

36

73

 

W. Wollaston

 

1803

Palladium

England

37

46

 

J. J. Berzelius, 

W. v. Hisinger,

M. H. Klaproth

 

1803

Cerium

Sweden

Germany

38

58

 

S. Tennant

 

1803

Osmium

England

39

76

 

S. Tennant

 

1803

Iridium

England

40

77

 

W. H.  Wollaston

 

1803

Rhodium

England

41

45

http://www.sapaviva.com/wp-content/uploads/2017/06/84.-John-Dalton-1766-1844-1-220x220.jpg

John Dalton

Revived, utilizing experimental evidence and work of Richter and Proust, the concept of atomos with the Dalton atomic theory.  Proposed law of multiple proportions and developed ranking of atomic masses (actually equivalent masses).

1803

 

England

 

 

Image result for gay-Lussac

Joseph Louis Gay-Lussac, Alexander von Humboldt,

H.  Cavendish

Gases at constant T and P combine in simple numerical proportions by volume, and the resulting product gases also bear a simple proportion by volume to the volumes of the reactants.

1808

 

France

 

 

 

Sir H. Davy

 

1807

Potassium

England

42

19

 

Sir H. Davy

 

1807

Sodium

England

43

11

 

Sir H. Davy

 

1808

Calcium

England

44

20

 

L. Gay-Lussac,

L-J. Thénard,

Sir H. Davy

 

1808

Boron

France,

England

45

5

 

Sir H. Davy

 

1808

Barium

England

46

56

 

Barnard Courtois

 

1811

Iodine

France

47

53

Amedeo Avogadro

Developed law that equal volumes of different gases contain the same number of molecules and the diatomic nature of many gases which many years later enabled chemists (~1860) to distinguish between equivalent and atomic masses.

1811

 

Italy

 

 

William Prout

Proposed concept that atomic weights of elements are whole-number multiples of the atomic weight of hydrogen suggesting that all elements are composed of hydrogen atoms.

1815

 

England

 

 

 

J. A. Arfvedson

 

1817

Lithium

Sweden

48

3

 

J. J. Berzelius

 

1817

Selenium

Sweden

49

34

 

F. Stromeyer

 

1817

Cadmium

Germany

50

48

 

J. J. Berzelius

 

1824

Silicon

Sweden

51

14

 

H. C. Oersted

 

1825

Aluminum

Denmark

52

13

 

Antoine Balard

 

1826

Bromine

France

53

35

Jöns Jacob. Berzelius

In addition to discovering elements, Berzelius published list of atomic weights (later vastly improved by Cannizzaro - 1860) and developed element symbols.

1828

Thorium

Sweden

54

90

Johann W. Döbereiner

Demonstrated concept of triads, groups of elements (later realized to be in the same group) in which the mass of the middle element was close to the average of the masses of the first and third element.

1829

 

Germany

 

 

  C. Mosander   1839 Lanthanum Sweden 55 57
Leopold
Gmelin


Using the concept of triads, developed a table of 55 elements in a periodic system that contained many of the important relationships of our modern periodic table.

https://www.meta-synthesis.com/webbook/35_pt/pt_database.php?PT_id=268

1843   Germany  
  C. Mosander   1843 Erbium Sweden 56 68

 

C. Mosander

 

1843

Terbium

Sweden

57

65

 

Karl K. Klaus

 

1844

Ruthenium

Russia

58

44

 

Peter Kremers

Extended the concept of triads from vertical to both vertical and horizontal relationships.

1856

 

Germany

 

 

 

R. W. Bunsen, G. R. Kirchhof

 

1860

Cesium

Germany

59

55

Stanislao Cannizzaro

 

 

Played important role in establishing useful table of atomic masses that enabled development within a decade of several periodic tables.

1860

 

Italy

 

 

 

R. W. Bunsen, G. R. Kirchhof

 

1861

Rubidium

Germany

60

37

 

W. Crookes

 

1861

Thallium

England

61

81

http://school-collection.lyceum62.ru/ecor/storage/autoindex/8bdecc58-3661-6478-bd3f-ac735c720882/00149189233405864/73923.jpg

Alexandre-Émile Béguyer de Chancourtois

Ordered elements according to increasing atomic mass in a chart that demonstrated periodic properties of the elements.

https://www.meta-synthesis.com/webbook/35_pt/pt_database.php?PT_id=7

1862

 

France

 

 

 

F. Reich,

H. T. Richter

 

1863

Indium

Germany

62

49

John Newlands

Ordered elements according to increasing atomic mass in a chart that demonstrated periodic properties of the elements and added rule of octaves.

https://www.meta-synthesis.com/webbook/35_pt/pt_database.php?PT_id=8

1864

 

England

 

 

See the source image

William Odling

Ordered elements according to increasing atomic mass in a chart that demonstrated periodic properties of the elements.

https://www.meta-synthesis.com/webbook/35_pt/pt_database.php?PT_id=91

1864

 

England

 

 

Gustavus Hinrichs

Gustavus Hinrichs

Ordered elements according to increasing atomic mass in a spiral chart that demonstrated periodic properties of the elements.  Used spectral evidence.

https://www.meta-synthesis.com/webbook/35_pt/pt_database.php?PT_id=270

1867

 

Denmark, U.S.

 

 

 

Jules Janssen

 

1868

Helium

France

63

2





Dimitri Mendeleev

Shares with Meyer recognition for predecessor of modern periodic table with elements ordered by atomic mass and groups determined by chemical properties.  Te and I placed correctly despite inverted masses.

https://www.meta-synthesis.com/webbook/35_pt/pt_database.php?PT_id=9

1868,

1869

 

Russia

 

 


Lothar Meyer

Shares with Mendeleev recognition for predecessor of modern periodic table with elements ordered by atomic mass and groups determined by chemical properties.

https://www.meta-synthesis.com/webbook/35_pt/pt_database.php?PT_id=12

1868,

1870

 

Germany

 

 

 

P.  Boisbaudran

 

1875

Gallium

France

64

31

 

J. C. G.  Marignac

 

1878

Ytterbium

Switzerland

65

70

 

Per T. Cleve

 

1878

Holmium

Sweden

66

67

 

Lars F. Nilson

 

1879

Scandium

Sweden

67

21

 

Per T. Cleve

 

1879

Thulium

Sweden

68

69

 

P.  Boisbaudran

 

1879

Samarium

France

69

62

 

J. C. G.  Marignac

 

1880

Gadolinium

Switzerland

70

64

 

C. F. A. Welsbach

 

1885

Praseodymium

Germany

71

59

 

C. F. A. Welsbach

 

1885

Neodymium

Austria

72

60

 

C. Winkler

 

1886

Germanium

Germany

73

32

 

P.  Boisbaudran

 

1886

Dysprosium

France

74

66

 

Henri Moissan

 

1886

Fluorine

France

75

9

William Crookes

Developed Crookes tube (1975) enabling discovery of electron and also suggested atomic weights are an average of different kinds of atoms of the same element (concept of isotopes).

1886

 

England

 

 

 

Eugen Goldstein

Discovered rays that were eventually realized to be hydrogen nuclei or protons.

1886

 

Germany

 

 

 

W. Ramsay,  Lord Rayleigh

 

1894

Argon

England,

Scotland

76

18

 

W. Röntgen

Discovered X-rays.

1895

 

Germany

 

 

 

H. Becquerel

Discovered radioactivity that enabled Marie Curie and others to isolate radioactive elements that filled in gaps in periodic table and for Rutherford to design gold foil expt.

1896

 

France

 

 

 

 

 

1896

Europium

France

77

63

http://www.azquotes.com/picture-quotes/quote-the-electron-may-it-never-be-of-any-use-to-anybody-joseph-john-thomson-126-38-95.jpg

J. J. Thomson

Discovered electron using Crookes’ tube and demonstrated that this tiny negatively charged particle had a huge charge to mass ratio (e/m) and was present in atoms of all elements.   Also found evidence for protons.  In 1904, he proposed “plum pudding” model for atom that was disproved by Rutherford in 1911.

1897

 

 

 

 

 

W. Ramsay, M. M. Travers

 

1898

Krypton

Scotland

78

36

 

W. Ramsay, M. M. Travers

 

1898

Neon

Scotland

79

10

 

W. Ramsay, M. M. Travers

 

1898

Xenon

Scotland

80

54

Marie Curie,

Pierre Curie

With her husband Pierre, discovered polonium and later other radioactive elements.

 

1898

Polonium

France

81

84

 

M. & P. Curie

 

1898

Radium

France

82

88

 

A-L. Debierne

 

1899

Actinium

France

83

89

 

F. E. Dorn

 

1900

Radon

Germany

84

86

Max Planck

Began modern era of quantum mechanics when he showed that energy did not flow in a steady continuum, but was delivered in discrete packets called quanta with E = hn.

1900

 

Germany

 

 


William Ramsay

Discovery of inert gases in late 1890’s (helium observed in sun in 1868 but isolated by William Ramsay and Raleigh in 1895) by Ramsay and co-workers led Ramsay, Mendeleev and others to add inert gases to periodic table.  See:  https://www.meta-synthesis.com/webbook/35_pt/pt_database.php?Button=All

1902

 

Scotland

 

 

Hantaro Nagaoka

Proposed solar system like model of the atom but not accepted until gold foil experiment of Rutherford in 1911.

1904

 

Japan

 

 

Richard Abegg

Developed concept of valence and explained inertness of noble gases based on octave of electrons in outer shell

1904

 

Germany

 

 

Alfred Werner

Presented periodic table with substantial resemblance to most popular form used today.    https://www.meta-synthesis.com/webbook/35_pt/pt_database.php?PT_id=64

 

1905

 

Switzerland

 

 

Albert Einstein

Light which had been considered a form of electromagnetic waves, must also be thought of as particle-like.  Theories of relativity also are important considerations in electron orbitals of high atomic number.

1905

 

Germany

 

 

 

G. Urbain,

C. F. A. Welsbach Charles James

 

1907

Lutetium

France, Austria, U.S.

85

71

Jean Baptiste Perrin

Strongly supported atomic theory, laid groundwork for Thomson’s discovery of the electron and proposed solar system model for atom (not accepted until 1911).

1907

 

France

 

 

Antonius Johannes van den Broek

First to change ordering of elements from atomic mass to charge in the nucleus (later called atomic number).

1907

 

Netherlands

 

 

Robert Millikan

Oil drop experiment determined charge on electron and enabled calculation of mass of electron from Thomson’s e/m ratio.

1909

 

United States

 

 

http://www.sapaviva.com/wp-content/uploads/2017/06/14.-Ernest-Rutherford-1871-1937-1-308x308.jpg

Ernest Rutherford

Performed gold foil experiment that demonstrated nuclear model for atom with tiny nucleus but with almost all the mass of the atom.  Before gold foil experiment, he showed that alpha particles are helium nucleii.  Also, often given credit for discovery of proton (however, see Goldstein in 1886)

1911

 

England  (born in New Zealand)

 

 

Frederick Soddy

Worked with Rutherford and elevated Crooke’s suggestion of isotopes into a theory.  In 1913, Hevesy and Paneth provided evidence that isotopes chemically behave the same.

1912

 

England

 

 

Henry Moseley

Using X-rays, demonstrated that the number of protons (atomic number) as suggested by van den Broek instead of atomic mass is the correct basis for the ordering of the elements.

1913

 

England

 

 


Niels Bohr

Applied quantum theory to atoms.  Using a planetary model, derived a correct mathematical description of electron in hydrogen but model failed for multiple electron atoms.  Proposed Aufbau Principle.  Attempted to use electron structure to explain shape of periodic table.  Produced symmetrical periodic table that improved tables of T. Bayley and J. Thomsen and was improved again by E. Scerri in 1997.  https://www.meta-synthesis.com/webbook/35_pt/pt_database.php?PT_id=19 

1913,

1922

 

Denmark

 

 

 

K. Fajans,

Otto Göhring

 

1913

Protactinium

Germany

86

91

Gilbert Lewis

Developed concept of electron pairs, bonding and Lewis structures for atoms and molecules.  Expanded work on valence concepts of Richard Abegg.

1916

 

U.S. (CA)

 

 

 

I. Langmuir, C. Bury,

J. M. Smith

Arranged elements according to electron arrangement.

 

1919,

1921,

1924

 

U.S.,  England

 

 

Francis Aston

Invented mass spectrometer and using it, was the first to experimentally demonstrate existence of isotopes of many elements.

1922

 

England

 

 

 

G. C. Hevesy,

Dirk Coster

 

1923

Hafnium

Denmark

87

72

Edmund Stoner

Improved Bohr’s attempt to correlate periodic table with electron theory by adding a third quantum number.

1924

 

England

 

 

Louis-Victor de Broglie

Predicted wave nature of electrons and all matter.

1924

 

France

 

 

Wolfgang Pauli

Added spin quantum number to make 4 quantum numbers that enable strong correlation of electron orbital theory to experimental properties and shape of periodic table.  Introduced Pauli Exclusion Principle.

1924

 

Switzerland

 

 

Werner Heisenberg

Used matrix mechanics to mathematically describe electron orbitals.  His results were later shown to give results equivalent to  Schrödinger’s wave equations.  Known for important Heisenberg Uncertainty Principle.

1925

 

Germany

 

 

Erwin Schrödinger

Using concept of duality of matter, developed wave equations that, in theory, enable correct calculations of electron orbitals and properties.  Practically speaking, solving the equations requires simplifying assumptions.

1926

 

Austria

 

 

 

W. & I. Noddack,

Otto Berg

 

1925

Rhenium

Germany

88

75

Friedrich Hund

Produced Hund’s rule which enhance application of Bohr’s Aufbau Principle.

1927

 

Germany

 

 

Paul Dirac

Formulated relativistic form of quantum mechanics that described energy levels of electrons.

1928

 

England

 

 

Charles Janet

Developed left step periodic table.

https://www.meta-synthesis.com/webbook/35_pt/pt_database.php?PT_id=152

1928

 

France

 

 

James Chadwick

Confirmed existence of and determined the mass of the neutron.

1932

 

England

 

 

Erwin Madelung

Madelung’s rule based on Janet’s suggestions gives order of filling of electron orbitals.

https://www.meta-synthesis.com/webbook/35_pt/pt_database.php?PT_id=777

1936

 

Germany

 

 

 

C. Perrier, 

E. G. Segre

 

1937

Technetium

Italy

89

43

    Otto Hahn and Fritz Strassmann discovered nuclear fission that was explained and predicted by Lise Meitner. 1937,
1938
  Germany    
  Hans Bethe Discovered nuclear fusion in the sun. 1938   U.S. (N.Y.)  

 

M. Perey

 

1939

Francium

France

90

87

 

D. R. Corson, K.R. Mackenzie, Emilio Segré

 

1940

Astatine

U.S. (CA)

91

85

 

E. McMillan, 

P. H. Abelson

 

1940

Neptunium

U.S. (CA)

92

93

 

Glenn Seaborg,

E. McMillan,

 J. W. Kennedy, Arthur Wahl

 

1940

Plutonium

U.S. (CA)

93

94


 

Glenn Seaborg, Ralph James, Albert Ghiorso

 

1944

Curium

U.S. (CA)

94

96

 

Glenn Seaborg, Ralph A. James, L. O. Morgan Albert Ghiorso

 

1944

Americium

U.S. (CA)

95

95

 

J. .A. Marinsky,

L. E. Glendenin, C. D. Coryell

 

1945

Promethium

U.S. (TN)

96

61

Emilio Gino Segrè

Produced chart of isotopes arranged by increasing atomic number. 

https://www.meta-synthesis.com/webbook/35_pt/pt_database.php?PT_id=231

1945

 

Italy, U.S.

 

 

Glenn Seaborg

In addition to leading the group that used transmutation to synthesize many transuranium elements, produced most complete version of modern periodic table. 

https://www.meta-synthesis.com/webbook/35_pt/pt_database.php?PT_id=522

1945

 

U.S. (CA)

 

 

 

S. Thompson, Albert Ghiorso, Glenn Seaborg.

 

1949

Berkelium

U.S. (CA)

97

97

 

S. Thompson, Kenneth Street, Albert Ghiorso Glenn Seaborg

 

1950

Californium

U.S. (CA)

98

98

 

Albert Ghiorso

 

1952

Einsteinium

U.S.

99

99

 

Albert Ghiorso

 

1952

Fermium

U.S. (CA)

100

100

 

Albert Ghiorso, Bernard Harvey, Gregory Choppin, S. Thompson,  Glenn Seaborg

 

1955

Mendelevium

U.S. (CA)

101

101

 

Albert Ghiorso, T. Sikkeland,

Almon E. Larsh R. M. Latimer

 

1961

Lawrencium

U.S. (CA)

102

103


Maria G. Mayer, Hans Jensen

Developed nuclear shell model that contributes to understanding of nuclear stability.

 

1963

 

U.S.,

Germany

 

 


M. Gell-Mann,

 G. Zweig

Proposed quark model.  Although not needed to explain the periodic table, quarks enhance our understanding of the nucleus.

1964

 

 U.S.

 

 

 

Georgy Flerov

 

1964

Rutherfordium

USSR

103

104

 

Georgy Flerov

 

1966

Nobelium

USSR

104

102

 

disputed

 

1967

Dubnium

USSR or U.S.

105

105

 

Albert Ghiorso,

Y. Oganessian

 

1974

Seaborgium

U.S. (CA) or Russia

106

106

 

P. Armbruster, G. Münzenber

 

1981

Bohrium

Germany

107

107

 

P. Armbruster, G. Münzenber

 

1982

Meitnerium

Germany

108

109

 

P. Armbruster, G. Münzenber

 

1984

Hassium

Germany

109

108

 

S. Hofmann,

P. Armbruster, G. Münzenber

 

1994

Darmstadtium

Germany

110

110

 

P. Armbruster, G. Münzenber

 

1994

Roentgenium

Germany

111

111

 

S.Hofmann, Victor Ninov

 

1996

Copernicium

Germany

112

112

 

Y. Oganessian

 

1998

Flerovium

Russia

113

114

 

Y. Oganessian Ken Moody

 

2000

Livermorium

Russia,U.S.

114

116

 

Y. Oganessian Ken Moody

 

2003

Moscovium

Russia, U.S.

115

115

 

Y. Oganessian

 

2006

Oganesson

Russia

116

118

 

Y. Oganessian

 

2010

Tennessine

Russia, U.S.

117

117

 

Kosuke Morita

 

2012      

Nihonium

Japan

118

113

Mark Winter

Produces continuously updated website devoted to the Periodic Table.  https://www.webelements.com/

1993 - current

 

England

 

 

Eric R. Scerri

The Periodic Table:  Its Story and Its Significance, Oxford University Press, N.Y.  A history of the development of the periodic table.  https://www.chemistry.ucla.edu/directory/scerri-eric-r    https://www.scientificamerican.com/article/the-evolution-of-the-periodic-system/

2007

 

U.S.

 

 

Mark R. Leach

Updates hot links to most periodic table websites and element discoveries.

https://www.meta-synthesis.com/webbook/35_pt/pt_database.php?Button=All

2003- current

 

England

 

 

Related image Theodore Gray

http://periodictable.com/index.html   For an extensive list of periodic properties with graphing capabilities, visit: http://periodictable.com/Properties/A/CrustAbundance.htm

current   U.S.    

1Images of most contributors of concepts included but not discoverers of elements with the exceptions of Marie Curie and William Ramsay

2RGB codes used for colors of elements taken from Chemicool.  Color is unknown but suspected to be silvery for elements with dark blue font.

3Number of known elements.


 Three thead timeline for the development of the periodic table, atomic structure and electronic theory.

 

 

  

Year

#1

Concept of the atom

Periodic table based on properties

Theory of Periodic Table

 

 

 

 

 

440 BC

11

Democritus, Leucippus suggested that matter is made up of indivisible particles called “atomos”. 

 

 

340 BC

11

Aristotle, Plato reject atomos concept and claim matter is continuous.  Continuity of matter concept dominates for 2100 years until evidence emerges in support of the atomic theory (1803).

 

 

1778

23

 

Antoine. Lavoisier demonstrates conservation of mass (within detectable limits) in chemical reactions and prepares list of 33 substances including 23 elements arranged according to properties (gases, non-metals, metals, earths)

http://www.meta-synthesis.com/webbook/35_pt/pt_database.php?PT_id=3

 

1794

31

Jeremias B. Richter and Joseph Proust discovered laws of definite proportions and constant composition.

 

 

1803

41

Results of Richter and Proust are inconsistent with continuity concept of matter but explainable using atomos concept.  John Dalton introduced empirically based atomic theory.

1.  Elements are made of extremely small particles called atoms.

2.  Atoms of a given element are the same in size, mass and other properties; atoms of different elements differ in size, mass and other properties.

3.  Atoms cannot be subdivided, created or destroyed.

4.  Atoms of different elements combine in simple whole-number ratios to form chemical compounds.

5.  In chemical reactions, atoms are combined, separated or rearranged.

 

 

1815

47

 

William Prout proposed concept that atomic weights of elements are whole-number multiples of the atomic weight of hydrogen suggesting that all elements are composed of hydrogen atoms.

 


1829

54

 

Johann W.  Döbereiner demonstrated concept of triads, groups of elements (later realized to be in the same group) in which the mass of the middle element was close to the average of the masses of the first and third element.

 


1843

55

 

Leopold Gmelin using the concept of triads, developed a table of 55 elements in a periodic system that contained many of the important relationships of our modern periodic table.  https://www.meta-synthesis.com/webbook/35_pt/pt_database.php?PT_id=268  

 

1860

59

 

Stanislao Cannizzaro played important role in establishing useful table of atomic masses that enabled development within a decade of several periodic tables.

 

1862-1867

62

 

A.-É. Béguyer de Chancourtois,

F. Reich, H. T. Richter, John Newlands,

William Odling, Gustavus Hinrichs ordered elements according to increasing atomic mass in charts that demonstrated periodic properties of the elements.  https://www.meta-synthesis.com/webbook/35_pt/pt_database.php?Button=All

 

1868- 1870

63

 

Dimitri Mendeleev and independently Lothar Meyer published predecessors of modern periodic table with elements ordered by atomic mass and groups determined by chemical properties.  https://www.meta-synthesis.com/webbook/35_pt/pt_database.php?PT_id=9

https://www.meta-synthesis.com/webbook/35_pt/pt_database.php?PT_id=12

 

1886

75

William Crookes suggested atomic weights are an average of different kinds of atoms of the same element (concept of isotopes). Crookes in 1875 also developed Crookes’ tube which enabled discovery of electron (1897)

 

 

1886

75

Eugen Goldstein discovered rays that were eventually realized to be hydrogen nuclei or protons.

 

 

1895

76

W. Röntgen discovered X-rays.

 

 

1896

77

H. Becquerel discovered radioactivity that enabled Marie Curie and others to isolate radioactive elements and for Rutherford to design gold foil expt.

 

 


1897

77

J. J. Thomson using Crookes’ tube discovers electron and determines e/m ratio.

 

 

1898

80

 

With her husband Pierre, Marie Curie discovered polonium and later other radioactive elements that filled in gaps in periodic table.

 

1900

84

 

 

Max Planck initiated modern era of quantum mechanics when he showed that energy did not flow in a steady continuum, but was delivered in discrete packets called quanta with E = hn.

1902

84

 

William Ramsay and co-workers discovery of inert gases in late 1890’s (helium observed in sun in 1868 but isolated by William Ramsay and Raleigh in 1895) led Ramsay, Mendeleev and others to add inert gases to periodic table.  See:  https://www.meta-synthesis.com/webbook/35_pt/pt_database.php?Button=All  

 

1904

84

J. J. Thomson proposes “plum pudding” model of atom.

 

 

1904

84

Hantaro Nagaoka proposed solar system like model of the atom that was not accepted until gold foil experiment of Rutherford in 1911.  In 1907, Jean Baptiste Perrin also promoted solar system model for atom.

 

 

1905

84

 

Alfred Werner presented periodic table with substantial resemblance to most popular form used today.    https://www.meta-synthesis.com/webbook/35_pt/pt_database.php?PT_id=64  

 

Albert Einstein showed that light which had been considered a form of electromagnetic waves, must also be thought of as particle-like (photons). Einstein’s relativity theories also are important considerations in electron orbitals of high atomic number.

1907

85

 

Antonius Johannes van den Broek was the first to change ordering of elements from atomic mass to nuclear charge (later called atomic number).

 

1908

85

Robert Millikan’s  oil drop experiment determined charge on electron and enabled calculation of mass of electron from Thomson’s e/m ratio.

 

 

1911

85

Ernest Rutherford performed gold foil experiment that demonstrated nuclear model for atom with tiny nucleus with almost all of the mass of the atom.  Before gold foil experiment, he showed that alpha particles are helium nucleii.  Also often given credit for discovery of proton (however, see Goldstein in 1886)

 

 


1912

85

Frederick Soddy worked with Rutherford and elevated Crooke’s suggestion (1886) of isotopes into a theory. In 1913, Hevesy and Paneth provided evidence that isotopes chemically behave the same.

 

 

1913

85

Henry Moseley using X-rays, demonstrated that the number of protons (atomic number) as suggested by van den Broek instead of atomic mass is the correct basis for the ordering of the elements.

 

Niels Bohr applied quantum theory to atoms.  Using a planetary model, derived a correct mathematical description of the electron in hydrogen but model failed for multiple electron atoms.  Proposed Aufbau Principle.  Attempted to use electron structure with two quantum numbers (n, l) to explain shape of periodic table. 

1922

86

Francis Aston invented mass spectrometer and using it, was the first to experimentally demonstrate existence of isotopes of many elements.

Niels Bohr produced symmetrical periodic table that improved tables of T. Bayley and J. J. Thomson and was improved again by E. Scerri in 1997.  https://www.meta-synthesis.com/webbook/35_pt/pt_database.php?PT_id=19

 

1924

87

 

 

Edmund Stoner improved Bohr’s attempt to correlate periodic table with electron theory by adding a third quantum number (n, l, m).

1924

87

 

 

Wolfgang Pauli added spin quantum number to make 4 quantum numbers (n, l, m, s) that enable strong correlation of electron orbital theory with experimental properties and shape of periodic table.  Introduced Pauli Exclusion Principle (all electrons for an atom must have distinct set of quantum numbers).

1924

87

 

 

Louis-Victor de Broglie showed wave nature of electrons and all matter.

1925, 1926

87

 

 

Werner Heisenberg and Erwin Schrödinger using different approaches, developed wave mechanical equations for correctly describing electronic orbitals.  Practically speaking, equations are extremely difficult to solve without making simplifying assumptions.

1927

88

 

 

Friedrich Hund produced Hund’s rule (every orbital in a sublevel is singly occupied before any orbital is doubly occupied) which enhanced application of Bohr’s Aufbau Principle.

1928

88

 

Charles Janet developed left step periodic table.  https://www.meta-synthesis.com/webbook/35_pt/pt_database.php?PT_id=152  

Paul Dirac formulated relativistic form of quantum mechanics that described energy levels of electrons.


1932

88

James Chadwick confirmed existence of and determined the mass of the neutron.

 

 

1936

88

 

 

Erwin Madelung’s rule based on Janet’s suggestions gives order of filling of electron orbitals.

https://www.meta-synthesis.com/webbook/35_pt/pt_database.php?PT_id=777

1936
...
    Nuclear reactions including transmutation, nuclear fission and nuclear fusion are discovered and exploited.
 

1945

96

Emilio Gino Segrè produced chart of isotopes arranged by increasing atomic number. 

https://www.meta-synthesis.com/webbook/35_pt/pt_database.php?PT_id=231  

Glenn Seaborg, in addition to leading the group that used transmuation to synthesize many transuranium elements, produced most complete version of modern periodic table.  https://www.meta-synthesis.com/webbook/35_pt/pt_database.php?PT_id=522  

 

1963

102

Maria G. Mayer, Hans Jensen developed nuclear shell model that contributes to understanding of nuclear stability.

 

 

1964

102

M. Gell-Mann, George Zweig proposed quark model.  Although not needed to explain the periodic table, quarks enhance our understanding of the nucleus.

 

 

2007

116

 

Eric R. Scerri authors The Periodic Table:  Its Story and Its Significance, Oxford University Press, N.Y.  A history of the development of the periodic table. https://www.chemistry.ucla.edu/directory/scerri-eric-r    https://www.scientificamerican.com/article/the-evolution-of-the-periodic-system/

 

1993-

 

 

2018

109

 

 

118

 

Mark Winter posted website devoted to the Periodic Table that is continually updated.  https://www.webelements.com/

 

2003

 

 

 

2018

114

 

 

 

118

 

Mark R. Leach posted hot links to most periodic table sites and element discoveries.  https://www.meta-synthesis.com/webbook/35_pt/pt_database.php?Button=Al .

 

...
2018 

118 
  Theodore Gray provides commercially available beautiful periodic tables and website with extensive list of properties with grpahing capibilities. http://periodictable.com/index.html
http://periodictable.com/Properties/A/CrustAbundance.html
 

1images generally only provided for conceptual contributions and not for discoverers of elements (exceptions include Curie and Ramsay)

2number of known elements discovered by the year indicated.

 

The excellent book by Eric R. Scerri (The Periodic Table:  Its Story and Its Significance, 2007, Oxford University Press, N.Y.) and the web site of Mark Leach

(https://www.meta-synthesis.com/webbook/35_pt/pt_database.php?Button=All)

were the sources of much of the information included in the timelines.

 

Medium-long forms of the periodic table with element colors.

A limited search for a periodic table with the colors of the elements has not yet located a table of this type.  However, Theodore Gray has produced many wonderful tables including one with images of authentic samples of the elements (http://periodictable.com/) and a commercially available model that contains sample of most of the elements (http://www.periodictable.co.uk/).  While the tables below are not nearly as fascinating or interesting as Gray's tables, the tables below have been designed to enable viewers to focus on the property of color.  Most of the colors have been extracted from https://www.chemicool.com/ primarily because it often included a two word description of the color.  Other sites referred to were Theodore Gray's http://periodictable.com/Properties/A/Color.html and Mark Winter's https://www.webelements.com/.   For some elements, the colors listed on Internet sites are not always in agreement.  Rene Vernon, the author of a paper on metalloids,  https://pubs.acs.org/doi/pdfplus/10.1021/ed3008457 has contributed valuable comments about the colors of boron, phosphorus, iodine, cesium and astatine.  Some of these color issues are because the most stable allotrope (e.g., phosphorus) is not always the most abundant allotrope.

boron - the most stable allotrope of boron is the beta rhombohedral crystalline state.  Colors reported for this state range from shiny silver-grey to grey to dark to black.   It is represented as dark grey below.

phosphorus - the most stable allotrope is black but the most common form is described as white to pale yellow.  A very light yellow has been used below with a black insert.

iodine - while silver is sometimes mentioned, the overwhelming consensus is that iodine crystals are in the violet or purple range.

astatine - although astatine has been observed, due to its transient existence, it has apparently not been possible to determine its color.  Some web sites conclude that it should have some metallic properties and as a result have a silvery color.  Other web sites suggest as progression is made down group 7A (17), the color continuously darkens with a presumption that astatine should be near black.  It is left in these tables as unknown like francium and the elements with atomic numbers above 99.

 

 

Selected periodic properties of the elements (ionization energy, atomic radius, valence).

For an extensive list of periodic properties with graphing capabilities please visit: 

http://periodictable.com/Properties/A/CrustAbundance.html
.







 
 

















Some periodic table questions and unresolved issues.

 1.  There are at least four commonly used versions of the periodic table:  the long, the medium-long, the left step, and the pyramidal.  While some experts have preferences for one or another, each has strengths and weaknesses.  Which one do you prefer and why?

medium-long and long (not up-to-date with names)

https://www.meta-synthesis.com/webbook/35_pt/pt_database.php?PT_id=371 (medium long and long but not up-to-date with names)

long form

https://commons.wikimedia.org/wiki/File:Periodic_table_large-long.svg

https://kaiserscience.wordpress.com/chemistry/the-periodic-table/alternative-periodic-tables/

medium-long form

https://iupac.org/what-we-do/periodic-table-of-elements/

https://www.webelements.com/

http://murov.info/pertab-trad.pdf

left step

https://jeries.rihani.com/symmetry/index6c.html

pyramidal version (not up-to-date with names)

https://www.meta-synthesis.com/webbook/35_pt/pt_database.php?PT_id=19

 

2.  The positions of some elements in periodic tables are still disputed. 

a.  Does hydrogen belong in the alkali metals group or the halogen group or neither?

b.  There are some claims that second period elements have properties inconsistent with the remaining members of their groups.  Explain this statement.

c.  Some medium-long periodic tables have lanthanum part of the “f” group of elements (split out from the periodic table), others have lutetium as a member of the 14 elements and still others include 15 elements in the “f” group .  What is the best placement of these two elements?  Part of the issue is the priority of chemical properties versus electronic structure.  If electronic structure is taken as the determining criteria, are there other elements that are misplaced in the periodic table?

 

3.  The IUPAC numbers the groups from 1 through 18 but American periodic tables often have A and B group elements with the numbers running from 1A through 8A and 1B through 8B.  State the advantages and disadvantages of each and your preference (for a table with both, see tables above or:  http://murov.info/pertab-trad.pdf.

 

4.  Is the periodic table universal or could there be differences on another planet?  For example, consider the universality of atomic masses.

 

5.  Does the periodic table contain any isotope information?  Consider use of the atomic mass as a source of isotope information (See:  S. Murov, Chem 13 News, March, 2010.  “Promoting Insight:  Atomic Mass”.

 

6.  The periodic tables above attempt to illustrate the approximate colors of the elements.  The orange staircase in the two periodic tables is commonly included in many periodic tables to very qualitatively separate the metals and the non-metals.  Do the colors of the elements also help to distinguish metals from non-metals and, if so, does this method correlate with the staircase model?  Which method do you think has more merit?  (Note:  It is often suggested that the elements adjacent to the staircase are metalloids, semiconductors and/or semimetals.  The consensus is that boron, silicon, germanium, arsenic, antimony and tellurium are metalloids with a few others in the questionable category.  For a discussion of criteria used to characaterize metalloid properties, please see:  https://pubs.acs.org/doi/pdfplus/10.1021/ed3008457 ).

 

7.  Calculations indicate that stability of nuclei depend on the neutron to proton ratio and predict an island of stability above atomic number 110.  Is it possible that there are some “longer lived isotopes” with atomic number above 110?  (e.g., see:  https://en.wikipedia.org/wiki/Island_of_stabilitybeyond_118)

 

8.  What is the probability that elements with atomic number greater than 118 will ever be synthesized?

(e.g., see:  https://www.chemistryworld.com/news/beyond-element-118-the-next-row-of-the-periodic-table/9400.article

 

9.  In some cases, discoveries have been made virtually simultaneously by different people in different countries (e.g., 1772, 1963).   Is this just a coincidence or are other factors in play here?

 

Suggestions, corrections and comments will be appreciated.  Please send them to Steven Murov at:  murovs@yosemite.edu
For a list of web sites posted by Steven Murov, please visit:  http://murov.info/  . 

For a Periodic table website, please visit: https://www.meta-synthesis.com/webbook/35_pt/pt_database.php?Button=Alhttp://murov.info/periodictables.htm  

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