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Group →	7
↓ Period
4	25  Mn
5	43  Tc
6	75  Re
7	107  Bh

A Group 7 element is one in the series of elements in group 7 (IUPAC style) in the periodic table, which consists of the transition metals manganese (Mn), technetium (Tc), rhenium (Re), and bohrium (Bh).

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

Z	Element	No. of electrons/shell
25	manganese	2, 8, 13, 2
43	technetium	2, 8, 18, 13, 2
75	rhenium	2, 8, 18, 32, 13, 2
107	bohrium	2, 8, 18, 32, 32, 13, 2

All of these elements are classed in Group 7 because their valence shells hold seven electrons. Technetium has no stable isotopes. Technetium and promethium are the only two such elements before lead, after which (with bismuth having an extremely long-lived isotope) no known element has a stable isotope.

[edit] Occurrence

Two of the four members of the group 2, technetium and bohrium, are radioactive with short enough half life that they are not present in nature. Furthermore rhenium is a rare element which occurs only in traces in other mineral. These facts make manganese the only abundant element of the group. This is also shown in difference in the annual world production. In 2007 11 million metric tons of manganese were mined while in the same year the world production of rhenium was between 40 and 50 metric tons.

[edit] See also

Explanation of right side periodic table slice:

Transition metals

atomic number in black are solids

solid borders are older than the Earth (Primordial elements)

dotted borders are made artificially (Synthetic elements)

dashed borders have no isotopes older than the earth

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