Alternative periodic tables
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Alternative periodic tables are chemical element displays different from the well known Mendeleev periodic table. Several have been devised often purely for didactic reasons as not all correlations between the chemical elements are effectively captured by the standard periodic table. The definitive work is Mazurs <ref>Mazurs, E. G. Graphical Representations of the Periodic System During One Hundred Years. Alabama; University of Alabama Press, 1974. ISBN 0817332006.</ref>.
In Thoedor Benfey's periodic table (1960) the elements spiral out in two dimensions starting from hydrogen folding their way around two islands, the transition metals & lanthanides and actinides. A superactinide island is already slotted in. In the Chemical Galaxy (2004) the elements spiral out in a similar way.
In the Extended periodic table, suggested by Glenn T. Seaborg in 1969, yet unknown elements are included up to atomic number 218. Helium is placed in the group 2 elements
Timmothy Stowe created the physicist's periodic table. This table is three-dimensional and the three axes represent the principal quantum number, orbital quantum number, and orbital magnetic quantum number. Helium is again a group 2 element.
Paul Giguere's 3-D periodic table consists of 4 billboards with the elements written on the front and the back. The first billboard has the group 1 elements on the front and the group 2 elements at the back with hydrogen and helium omitted altogether. At a 90° angle the second billboard contains the groups 13 to 18 front and back. Two more billboard each making 90° angles contain the other elements.
In the research field of superatoms, clusters of atoms have properties of single atoms of another element. It is suggested to extend the periodic table with a second layer to be occupied with these cluster compounds. The latest addition to this multi-storey table is the aluminum Al7- cluster which nehaves like a multivalent germanium atom <ref>Beyond The Periodic Table Metal clusters mimic chemical properties of atoms Ivan Amato Chemical & Engineering News November 21, 2006 Link</ref>
In a commentary R.L. Rich <ref>Rich, Ronald L. J. Chem. Educ. 2005 82 1761</ref> proposes a periodic table where elements appear more than once when appropriate. He notes that hydrogen shares properties with group 1 elements based on valency, with group 17 elements because hydrogen is a non-metal but also with the carbon group based on similarities in chemical bonding to transition metals and a similar electronegativity. In this rendition of the periodic table carbon and silicon also appear in the same group as titanium and zirconium.
[edit] Circular form of periodic table
The major disadvantage of the Standard Periodic table is its shape itself. Rectangular arrangement of elements puts constraints in describing the properties of the elements such as shape, atomic structure, nucleus, etc. With the developments in the nucleon shell model it is far more informative to have a complete periodic table showing both nucleon as well as electronic structure.
To incorporate more and more amount of properties in a form of arrangement of elements a new circular of periodic table is put forward by Mohd Abubakr (Hyderabad, India). The aim of this circular form of table is make a student understand the atomic structure and its properties along side the periodic table. This table does include all the properties of the Modern Periodic table meanwhile adding further advantages.
Salient features of Circular Form of Periodic Table:
- It clearly reflects the atomic structure of an element along with the electronic configuration.
- It shows pictorially the arrangement of electrons outside the nucleus.
- Atomic nucleus is also shown in the circular form of periodic table, which was absent in any modern form of periodic table.
- This periodic table is based on the Bohr’s model of Atomic structure.
- Once the nucleon shell model gets fully developed, in can be incorporated in the table easily.
- Properties like atomic radius, ionization energy, electron affinity, electro negativity metallic character, binding energies, diagonal relationships can be explained in far more convenient way using Circular form of Periodic Table.
- Since in the atoms, as the orbits are filled with electrons in the order n = 1, n =2 ,n=3,… the shells are formed. There are 7 shells in the table each representing a unique energy level. (Each shell is shown with a unique color)
- The Circular periodic table consists of 18 sectors called as groups similar to Modern periodic table.
- Considering the size and shape of hydrogen and helium atoms they are shown much closer to nucleus.
[edit] References
[edit] External links
- The Thoedor Benfrey periodic table
- Periodic Table of the Elements (Janet form)
- A Correction to Physicist periodic table offered by Jeries Rihani as Meitnerium occupies the position that Hassium should have.
- The Paul Giguere 3-D periodic table requires Quicktime
- A Wired Article on Alternate Periodic Tables
- A Selection of Periodic Tables
- Janet periodic table
- Albert Tarantola's Periodic Table (1975)
