Alternative periodic tables are tabulations of chemical elements differing significantly in their organization from the Mendeleev periodic table.^[1][2] 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. A 1974 review of the tables then known^[3] is considered a definitive work on the topic.

Contents 1 Aims 2 Major alternatives 3 References 4 External links

[edit] Aims

Alternative periodic tables are developed often to highlight or emphasize different chemical or physical properties of the elements which are not as apparent in traditional periodic tables. Some tables aim to emphasize both the nucleon and electronic structure of atoms. This can be done changing the spatial relationship or representation each element has with respect to another element in the table. Other tables aim to emphasize the chemical element isolations by humans over time.

[edit] Major alternatives

Janet's Left Step Periodic Table (1928) is considered to be the most significant alternative to the traditional depiction of the periodic system. It organizes elements according to orbital filling and is widely used by physicists. Its modern version, known as ADOMAH Periodic Table, (2006) is helpful for writing electron configurations.^[4]

In Theodor Benfey's periodic table (1960), the elements form a two-dimensional spiral, starting from hydrogen, and folding their way around two islands, the transition metals, and lanthanides and actinides. A superactinide island is already slotted in. The Chemical Galaxy (2004) is organized 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's physicist's periodic table is three-dimensional with the three axes representing 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-story table is the aluminum cluster ion Al−7, which behaves like a multivalent germanium atom.^[5]

Ronald L. Rich has proposed a periodic table where elements appear more than once when appropriate.^[6] 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] References

[edit] External links

• Janet's Left Step Periodic Table
• Correction to Physicist periodic table offered by Jeries Rihani as Meitnerium occupies the position that Hassium should have.
• A Wired Article on Alternate Periodic Tables
• A Selection of Periodic Tables
• http://periodicspiral.com/ arranges the periodic table in a (hexagonal) spiral.
• Rotaperiod.com A new periodic table.
• Note on the T-shirt topology of the Z-spiral.
• New Periodic Table of the Elements this is in a square-triangular periodic arrangement
• Periodic Table based on electron configurations
• Database of Periodic Tables
• Periodic Fractal of the Elements

v • d • e Periodic tables Layouts Standard · Inline f-block · Vertical · Full names · Names and atomic weights · Text for last · Large table · Metals and nonmetals · Blocks · Valences · Extension beyond the 7th period · Electron configurations · Atomic weights · Electronegativities · Alternatives · Crystal structure Lists of elements by Name · Atomic symbol · Atomic number · Atomic weight · Name etymology (after places, after people) · Discovery Boiling point · Melting point · Density · Oxidation state · Abundance (in humans) · Nuclear stability · Hardness Groups 1 (Alkali metals) · 2 (Alkaline earth metals) · 3 · 4 · 5 · 6 · 7 · 8 · 9 · 10 · 11 · 12 · 13 (Boron group) · 14 (Carbon group) · 15 (Pnictogens) · 16 (Chalcogens) · 17 (Halogens) · 18 (Noble gases) Periods 1 · 2 · 3 · 4 · 5 · 6 · 7 · 8 Other element categories Metals · Transition metals (1st row) · Metalloids · Nonmetals · Lanthanoids · Actinoids · Rare earth elements · Platinum group metals (PGMs) · Post-transition metals Blocks s-block · p-block · d-block · f-block