Group 8 element

Template:Periodic table (group 8) Group 8 is a group (column) of chemical element in the periodic table. It consists of iron (Fe), ruthenium (Ru), osmium (Os) and hassium (Hs). They are all transition metals.

Like other groups, the members of this family show patterns in electron configuration, especially in the outermost shells, resulting in trends in chemical behavior.

"Group 8" is the modern standard designation for this group, adopted by the IUPAC in 1990.

In the older group naming systems, this group was combined with group 9 (cobalt, rhodium, iridium, and meitnerium) and group 10 (nickel, palladium, platinum, and darmstadium) and called group "VIIIB" in the Chemical Abstracts Service (CAS) "U.S. system", or "VIII" in the old IUPAC (pre-1990) "European system" (and in Mendeleev's original table).

Group 8 (current IUPAC) should not be confused with "group VIIIA" in the CAS system, which is group 18 (current IUPAC), the noble gases.

While groups (columns) of the periodic table are sometimes named after their lighter member (as in "the oxygen group" for group 16), the term iron group most often means a set of adjacent elements on period (row) 4 of the table that includes iron, such as chromium, manganese, iron, cobalt, and nickel; or only the last three; or some other set — depending on the context.

Basic properties

Z	Element	No. of electrons per shell	M.P.	B.P.	Year of Discovery	Discoverer
26	iron	2, 8, 14, 2	1811 K 1538 °C	3134 K 2862 °C	<3000 BCE	Unknown
44	ruthenium	2, 8, 18, 15, 1	2607 K 2334 °C	4423 K 4150 °C	1844	K. E. Claus
76	osmium	2, 8, 18, 32, 14, 2	3306 K 3033 °C	5285 K 5012 °C	1803	S. Tennant and W. H. Wollaston
108	hassium	2, 8, 18, 32, 32, 14, 2	—	—	1984	P. Armbruster and G. Münzenberg

The first three elements are hard silvery-white metals. Hassium has not been isolated in macroscopic pure form, and its properties have not been conclusively observed.

Occurrence

Iron is the most common element within the entire earth; most of the core is iron and there is a substantial amount of iron in the mantle and crust as well. Ruthenium and osmium are two of the rarest elements on earth, with ruthenium found only in small amounts in platinum ores. Osmium is the least abundant stable element in the earth's crust, found only in minor traces in platinum ores. Hassium is produced only in nuclear reactors and has never been observed in nature nor isolated in pure form.

Biological role

Iron is an essential nutrient for all living organisms, from archaea to humans. It is a major component in hemoglobin, a protein that makes blood red and transfers oxygen to muscles, and is also found in many other proteins. Ruthenium, osmium, and hassium have no known role in the human body.