Post-transition metals Group # 12 13 14 15 Period 4 30 Zn 31 Ga 5 48 Cd 49 In 50 Sn 6 80 Hg 81 Tl 82 Pb 83 Bi

Atomic numbers show state at STP Solids Liquids

In chemistry, the term post-transition metal is used to describe the category of metallic elements to the right of the transition elements on the periodic table^[1][2]. IUPAC defines "transition elements" as either the elements in groups 3–11 or the elements in groups 3–12^[3]. According to the first definition, post-transition metals include group 12—zinc, cadmium, and mercury. This collection of elements is illustrated by the element boxes to the right. Occasionally germanium, antimony, and/or polonium are also included as metals, although these are usually considered to be metalloids. According to the second definition of transition elements, group 12 would not be included as a post-transition metal. An examination of textbooks and monographs in 2003 revealed that both definitions are used with roughly equal frequency^[4].

In the 1950s, most inorganic chemistry textbooks defined transition elements as excluding group 11—copper, silver, and gold in addition to group 12^[4]. A third definition of post-transition metal that includes group 11 and group 12 elements is no longer recommended by IUPAC^[3] but is still used on occasion^[5][6].

Contents 1 Poor metals 2 References 2.1 Notes 2.2 Bibliography 3 External links

[edit] Poor metals

The trivial name poor metals is sometimes applied to the metallic elements in the p-block of the periodic table. Their melting and boiling points are generally lower than those of the transition metals and their electronegativity higher, and they are also softer. They are distinguished from the metalloids, however, by their significantly higher boiling points in the same row.

"Poor metals" is not a rigorous IUPAC-approved nomenclature, but the grouping is generally taken to include aluminium, gallium, indium, tin, thallium, lead, and bismuth. Occasionally germanium, antimony, and polonium are also included, although these are usually considered to be metalloids or "semi-metals". Elements 113 to 116, which are currently allocated the systematic names ununtrium, ununquadium, ununpentium and ununhexium, would likely exhibit properties characteristic of poor metals;^{[citation needed]} however sufficient quantities of them have not yet been synthesized to examine their chemical properties.

13	14	15	16
Al Aluminium
Ga Gallium	Ge Germanium
In Indium	Sn Tin	Sb Antimony
Tl Thallium	Pb Lead	Bi Bismuth	Po Polonium
Uut ununtrium	Uuq ununquadium	Uup ununpentium	Uuh ununhexium

[edit] References

[edit] Notes

[edit] Bibliography

• The Chemistry Student's Companion, Stephen Schaffter, Lulu Press, Inc, 2006. ISBN 1-4116-9247-0.

[edit] External links

• Patent-Invent - Poor Metals Quick Facts
• Royal Armouries - Poor Metals

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