Periodic Table |
 |
 |
 |
 |
 |
 |
 |
| What is the Periodic Table Showing? | Periodicity |
The INTERNET Database of Periodic Tables
There are thousands of periodic tables in web space, but this is the only comprehensive database of periodic tables & periodic system formulations. If you know of an interesting periodic table that is missing, please contact the database curator: Mark R. Leach Ph.D. The database hold information on periodic tables, the discovery of the elements and elucidation of atomic weights (and more).
The 10 Periodic Tables most recently added to the database:
| Year: 2025 | PT id = 1366, Type = formulation review |
The Surprisingly Beautiful Origins of the Periodic Table
A video about The Surprisingly Beautiful Origins of the Periodic Table by Chemistorian.
"The periodic table is probably the most iconic image in science. Join me to hear the story about its origins, from ancient philosophers speculating about the nature of matter to the earliest chemists who tried to find the mysterious connection between the elements. Learn about Döbereiner's chemical traids, De Chancourtois' Telluric Screw, Mendeleev's amazing predictions, and much more!"
Thanks to Eric Scerri for the tip!
| Year: 2026 | PT id = 1365, Type = formulation |
Pairs and Squares Periodic Table
"Pairs and Squares" Periodic Table by Leonid A. Levin of Boston University
Leonid writes:
"All the tables [in the PT Database] share a common problem: their irregularity exceeds by far their periodicity.
"In my youth I was greatly bothered by this. Yet, taking advantage of a few patterns in atomic orbitals allows a complete elimination of all irregularities, putting all periods in a perfect pattern.This perfectly regular rendition would be much more comfortable, especially at one's first high school exposure to this Science symbol.I am attaching such "Pairs and Squares" rendition with a brief explanation."
"Read more in the full 'Pairs and Squares' paper, here."
| Year: 2007 | PT id = 1364, Type = formulation |
Distribuzione Peridica Degli Elemnti
Distribuzione Peridica Degli Elemnti – Periodic Distribution of Elements – by Leonello Paoloni.
From La Chimica nella Scuola, Sept. 2007, pp 111.
"Fig. 2. The periodic distribution of elements correlates with the group distribution of atomic electrons. Groups are formed so that all elements of the same family are found in corresponding positions (for example, the halogens are always in the second-to-last position in a group of six elements)." (Google Translate)
Thanks to Eric Scerri for the tip!
| Year: 1873 | PT id = 1363, Type = formulation review element weight |
Annual Report on the Progress of Chemistry and Related Areas of Other Sciences 1873
Jahresbericht über die Fortschritte der Chemie und verwandter Theile anderer Wissenschaften. (Annual Report on the progress of chemistry and related areas of other sciences.) HathiTrust Index scanned reports 1847-1910.
The 1873 table of data is here.
Mark Leach writes:
"Every year the annual report started with a list of the known chemical elements and their atomic weights, however, to the modern eye there were many systematic errors. For example, oxygen (Sauerstoff) is given as having a weight of 8 which would have caused – due to the importance of oxides – other atomic weights to be out by a factor of 2 or 3. Once a list of correct atomic weights was known, it would be possible to construct a periodic table of the elements.
"In 1858 the Cannazzario letter gave more correct list of atomic weights and corrected the numerous stoichiometric errors that plagued chemistry at the time. Over the years from 1858 to 1873 the entries in the annual report gradually adopted the Cannazzario logic."
Notes:
- Didym D = 48 was actually a mixture of rare earth elements.
- Ilmenium, Il, was later found to be a mixture of niobium and tantalum.
- Generally, the elements missing had yet to be discovered (dates given below).
- The table below shows the progress from 1858 to 1873.
- By 1873 the only elements with incorrect atomic weights were the (at the time) somewhat obscure strontium, lanthanium, cerium and urananium.
- Previously, many elements were shown with two entries. Clearly, the stoichiometric and mass problems had largely been resolved (and the data agreed upon) by 1873.
Thanks to René and Mario Rodriguez for the tip!
| Year: 1872 | PT id = 1362, Type = formulation element weight |
Annual Report on the Progress of Chemistry and Related Areas of Other Sciences 1872
Jahresbericht über die Fortschritte der Chemie und verwandter Theile anderer Wissenschaften. (Annual Report on the progress of chemistry and related areas of other sciences.) HathiTrust Index scanned reports 1847-1910.
The 1872 table of data is here.
Mark Leach writes:
"Every year the annual report started with a list of the known chemical elements and their atomic weights, however, to the modern eye there were many systermatic errors. For example, oxygen (Sauerstoff) is given as having a weight of 8 which would have caused – due to the importance of oxides – other atomic weights to be out by a factor of 2 or 3. Once a list of correct atomic weights was known, it would be possible to construct a periodic table of the elements.
"In 1858 the Cannazzario letter gave more correct list of atomic weights and corrected the numerous stoichiometric errors that plagued chemistry at the time. Over the years from 1858 to 1873 the entries in the annual report gradually adopted the Cannazzario logic."
- Didym Di = 48 and 95 was actually a mixture of rare earth elements.
- The missing elements had yet to be discovered.
- Al = 13.7 and 27.4
- Ba = 68.5 and 137
- Be = 4.7 and 7.0
- Pb = 103.5 and 207
- Cd = 56 and 112
- Ca = 20 and 40
- Ce = 56 and 92
- Cr = 26 and 52
- Fe = 28 and 56
- Er = 56.3 and 112.6
- Ir = 99 and 198
- Co = 29.5 and 59
- C = 6 and 12
- Cu = 31.7 and 63.4
- La = 46.8 and 93.6
- Mg = 12 and 24
- Mn = 27.5 and 55
- Mo = 48 and 96
- Ni = 29.5 and 58
- Os = 100 and 200
- Pd = 53 and 106
- Pt = 99 and 198
- Hg = 100 and 200
- Rh = 52 and 104
- Ru = 52 and 104
- Si = 14 and 28
- O = 8 and 16
- S = 16 and 32
- Se = 39.5 and 79
- Sr = 43.8 and 87.6
- Te = 64 and 128
- Th = 57.8 and 115.6
- Ti = 25 and 50
- Wo = 92 and 184 (note change from W to Wo)
- Y = 29.8 and 59.7
- Zn = 32.5 and 65
- Sn = 59 and 118
- Zr = 45 and 90
Thanks to René and Mario Rodriguez for the tip!
| Year: 1871 | PT id = 1361, Type = formulation element weight |
Annual Report on the Progress of Chemistry and Related Areas of Other Sciences 1871
Jahresbericht über die Fortschritte der Chemie und verwandter Theile anderer Wissenschaften. (Annual Report on the progress of chemistry and related areas of other sciences.) HathiTrust Index scanned reports 1847-1910.
The 1871 table of data is here.
Mark Leach writes:
"Every year the annual report started with a list of the known chemical elements and their atomic weights, however, to the modern eye there were many systermatic errors. For example, oxygen (Sauerstoff) is given as having a weight of 8 which would have caused – due to the importance of oxides – other atomic weights to be out by a factor of 2 or 3. Once a list of correct atomic weights was known, it would be possible to construct a periodic table of the elements.
"In 1858 the Cannazzario letter gave more correct list of atomic weights and corrected the numerous stoichiometric errors that plagued chemistry at the time. Over the years from 1858 to 1873 the entries in the annual report gradually adopted the Cannazzario logic."
- Didym Di = 48 and 95 was actually a mixture of rare earth elements.
- The missing elements had yet to be discovered.
- Al = 13.7 and 27.4
- Ba = 68.5 and 137
- Be = 4.7 and 7.0
- Pb = 103.5 and 207
- Cd = 56 and 112
- Ca = 20 and 40
- Ce = 56 and 92
- Cr = 26 and 52
- Fe = 28 and 56
- Er = 56.3 and 112.6
- Ir = 99 and 198
- Co = 29.4 and 58.8
- C = 6 and 12
- Cu = 31.7 and 63.4
- La = 46.8 and 93.6
- Mg = 12 and 24
- Mn = 27.5 and 55
- Mo = 48 and 96
- Ni = 29.5 and 58
- Os = 100 and 200
- Pd = 53 and 106
- Pt = 99 and 198
- Hg = 100 and 200
- Rh = 52 and 104
- Ru = 52 and 104
- Si = 14 and 28
- O = 8 and 16
- S = 16 and 32
- Se = 39.5 and 79
- Sr = 43.8 and 87.6
- Te = 64 and 128
- Th = 57.86 and 115.72
- Ti = 25 and 50
- Wo = 92 and 184 (note change from W to Wo)
- Y = 30.8 and 61.6
- Zn = 32.5 and 65
- Sn = 59 and 118
- Zr = 45 and 90
Thanks to René and Mario Rodriguez for the tip!
| Year: 1870 | PT id = 1360, Type = formulation element weight |
Annual Report on the Progress of Chemistry and Related Areas of Other Sciences 1870
Jahresbericht über die Fortschritte der Chemie und verwandter Theile anderer Wissenschaften. (Annual Report on the progress of chemistry and related areas of other sciences.) HathiTrust Index scanned reports 1847-1910.
The 1870 table of data is here.
Mark Leach writes:
"Every year the annual report started with a list of the known chemical elements and their atomic weights, however, to the modern eye there were many systermatic errors. For example, oxygen (Sauerstoff) is given as having a weight of 8 which would have caused – due to the importance of oxides – other atomic weights to be out by a factor of 2 or 3. Once a list of correct atomic weights was known, it would be possible to construct a periodic table of the elements.
"In 1858 the Cannazzario letter gave more correct list of atomic weights and corrected the numerous stoichiometric errors that plagued chemistry at the time. Over the years from 1858 to 1873 the entries in the annual report gradually adopted the Cannazzario logic."
- Didym Di = 48 and 95 was actually a mixture of rare earth elements.
- The missing elements had yet to be discovered.
- Al = 13.7 and 27.4
- Ba = 68.5 and 137
- Be = 4.7 and 7.0
- Pb = 103.5 and 207
- Cd = 56 and 112
- Ca = 20 and 40
- Ce = 56 and 92
- Cr = 26.1 and 52.2
- Fe = 28 and 56
- Er = 56.3 and 112.6
- Ir = 99 and 198
- Co = 29.4 and 58.8
- C = 6 and 12
- Cu = 31.7 and 63.4
- La = 46.8 and 93.6
- Mg = 12 and 24
- Mn = 27.5 and 55
- Mo = 48 and 96
- Ni = 29.4 and 58.8
- Os = 100 and 200
- Pd = 53 and 106
- Pt = 99 and 198
- Hg = 100 and 200
- Rh = 52 and 104
- Ru = 52 and 104
- Si = 14 and 28
- O = 8 and 16
- S = 16 and 32
- Se = 39.5 and 79
- Sr = 43.8 and 87.6
- Te = 64 and 128
- Th =57.86 and 115.72
- Ti = 25 and 50
- Wo = 92 and 184 (note change from W to Wo)
- Y = 30.8 and 61.6
- Zn = 32.5 and 65
- Sn = 59 and 118
- Zr = 45 and 90
Thanks to René and Mario Rodriguez for the tip!
| Year: 1869 | PT id = 1359, Type = formulation element weight |
Annual Report on the Progress of Chemistry and Related Areas of Other Sciences 1869
Jahresbericht über die Fortschritte der Chemie und verwandter Theile anderer Wissenschaften. (Annual Report on the progress of chemistry and related areas of other sciences.) HathiTrust Index scanned reports 1847-1910.
The 1869 table of data is here.
Mark Leach writes:
"Every year the annual report started with a list of the known chemical elements and their atomic weights, however, to the modern eye there were many systermatic errors. For example, oxygen (Sauerstoff) is given as having a weight of 8 which would have caused – due to the importance of oxides – other atomic weights to be out by a factor of 2 or 3. Once a list of correct atomic weights was known, it would be possible to construct a periodic table of the elements.
"In 1858 the Cannazzario letter gave more correct list of atomic weights and corrected the numerous stoichiometric errors that plagued chemistry at the time. Over the years from 1858 to 1873 the entries in the annual report gradually adopted the Cannazzario logic."
- Didym Di = 48 and 95 was actually a mixture of rare earth elements.
- The missing elements had yet to be discovered.
- Al = 13.7 and 27.4
- Ba = 68.5 and 137
- Be = 4.7 and 7.0
- Pb = 103.5 and 207
- Cd = 56 and 112
- Ca = 20 and 40
- Ce = 56 and 92
- Cr = 26.1 and 52.2
- Fe = 28 and 56
- Er = 56.3 and 112.6
- Ir = 99 and 198
- Co = 29.4 and 58.8
- C = 6 and 12
- Cu = 31.7 and 63.4
- La = 46.8 and 93.6
- Mg = 12 and 24
- Mn = 27.5 and 55
- Mo = 48 and 96
- Ni = 29.4 and 58.8
- Os = 100 and 200
- Pd = 53 and 106
- Pt = 99 and 198
- Hg = 100 and 200
- Rh = 52 and 104
- Si = 14 and 28
- O = 8 and 16
- S = 16 and 32
- Se = 39.5 and 79
- Sr = 43.8 and 87.6
- Te = 64 and 128
- Th =57.86 and 115.72
- Ti = 25 and 50
- Wo = 92 and 184 (note change from W to Wo)
- Y = 30.8 and 61.6
- Zn = 32.5 and 65
- Sn = 59 and 118
- Zr = 44.8 and 89.6
Thanks to René and Mario Rodriguez for the tip!
| Year: 1868 | PT id = 1358, Type = formulation element weight |
Annual Report on the Progress of Chemistry and Related Areas of Other Sciences 1868
Jahresbericht über die Fortschritte der Chemie und verwandter Theile anderer Wissenschaften. (Annual Report on the progress of chemistry and related areas of other sciences.) HathiTrust Index scanned reports 1847-1910.
The 1868 table of data is here.
Mark Leach writes:
"Every year the annual report started with a list of the known chemical elements and their atomic weights, however, to the modern eye there were many systermatic errors. For example, oxygen (Sauerstoff) is given as having a weight of 8 which would have caused – due to the importance of oxides – other atomic weights to be out by a factor of 2 or 3. Once a list of correct atomic weights was known, it would be possible to construct a periodic table of the elements.
"In 1858 the Cannazzario letter gave more correct list of atomic weights and corrected the numerous stoichiometric errors that plagued chemistry at the time. Over the years from 1858 to 1873 the entries in the annual report gradually adopted the Cannazzario logic."
- Didym Di = 48 and 95 was actually a mixture of rare earth elements.
- The missing elements had yet to be discovered.
- Al = 13.7 and 27.4
- Ba = 68.5 and 137
- Be = 4.7 and 7.0
- Pb = 103.5 and 207
- Cd = 56 and 112
- Ca = 20 and 40
- Ce = 56 and 92
- Cr = 26.1 and 52.2
- Fe = 28 and 56
- Er = 56.3 and 112.6
- Ir = 99 and 198
- Co = 29.4 and 58.8
- C = 6 and 12
- Cu = 31.7 and 63.4
- La = 46.8 and 93.6
- Mg = 12 and 24
- Mn = 27.5 and 55
- Mo = 48 and 96
- Ni = 29.4 and 58.8
- Os = 100 and 200
- Pd = 53.3 and 106.6
- Pt = 99 and 198
- Hg = 100 and 200
- Rh = 52 and 104
- Si = 14 and 28
- O = 8 and 16
- S = 16 and 32
- Se = 39.7 and 79.4
- Sr = 43.8 and 87.6
- Te = 64 and 128
- Th =57.86 and 115.72
- Ti = 25 and 50
- Wo = 92 and 184 (note change from W to Wo)
- Y = 30.8 and 61.6
- Zn = 32.6 and 65.2
- Sn = 59 and 118
- Zr = 44.8 and 89.6
Thanks to René and Mario Rodriguez for the tip!
| Year: 1867 | PT id = 1357, Type = formulation element weight |
Annual Report on the Progress of Chemistry and Related Areas of Other Sciences 1867
Jahresbericht über die Fortschritte der Chemie und verwandter Theile anderer Wissenschaften. (Annual Report on the progress of chemistry and related areas of other sciences.) HathiTrust Index scanned reports 1847-1910.
The 1867 table of data is here.
Mark Leach writes:
"Every year the annual report started with a list of the known chemical elements and their atomic weights, however, to the modern eye there were many systermatic errors. For example, oxygen (Sauerstoff) is given as having a weight of 8 which would have caused – due to the importance of oxides – other atomic weights to be out by a factor of 2 or 3. Once a list of correct atomic weights was known, it would be possible to construct a periodic table of the elements.
"In 1858 the Cannazzario letter gave more correct list of atomic weights and corrected the numerous stoichiometric errors that plagued chemistry at the time. Over the years from 1858 to 1873 the entries in the annual report gradually adopted the Cannazzario logic."
- Didym Di = 48 and 95 was actually a mixture of rare earth elements.
- The missing elements had yet to be discovered.
- Al = 13.7 and 27.4
- Ba = 68.5 and 137
- Be = 4.7 and 7.0
- Pb = 103.5 and 207
- Cd = 56 and 112
- Ca = 20 and 40
- Ce = 56 and 92
- Cr = 26.1 and 52.2
- Fe = 28 and 56
- Ir = 99 and 198
- Co = 29.4 and 58.8
- C = 6 and 12
- Cu = 31.7 and 63.4
- La = 46.8 and 93.6
- Mg = 12 and 24
- Mn = 27.5 and 55
- Mo = 48 and 96
- Nb = 47 and 94
- Ni = 29.4 and 58.8
- Os = 99.6 and 199.2
- Pd = 53.3 and 106.6
- Pt = 98.7 and 197.4
- Hg = 100 and 200
- Rh = 52.2 and 104.4
- Si = 14 and 21 and 28
- O = 8 and 16
- S = 16 and 32
- Se = 39.7 and 79.4
- Sr = 43.8 and 87.6
- Ta = 68.8 and 172
- Te = 64 and 128
- Ti = 25 and 50
- Th =57.86 and 115.72
- W = 92 and 184
- Y = 30.8 and 61.6
- Zn = 32.6 and 65.2
- Sn = 59 and 118
- Zr = 22.4 and 33.6 and 44.8 and 89.6
Thanks to René and Mario Rodriguez for the tip!
|
|
|
| What is the Periodic Table Showing? | Periodicity |
© Mark R. Leach Ph.D. 1999 –
Queries, Suggestions, Bugs, Errors, Typos...
If you have any:
Queries
Comments
Suggestions
Suggestions for links
Bug, typo or grammatical error reports about this page,please contact Mark R. Leach, the author, using mark@meta-synthesis.com
This free, open access web book is an ongoing project and your input is appreciated.