Period 7 element

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A period 7 element is one of the chemical elements in the seventh row (or period) of the periodic table of the elements and all have 7 electron shells.

All elements of period 7 are radioactive. This period contains the heaviest element which occurs naturally on earth, uranium. Most of the subsequent elements in the period have been synthesized artificially. Whilst some of these (e.g. plutonium) are now available in tonne quantities, most are extremely rare, having only been prepared in microgram amounts or less. Some of the later elements have only ever been identified in laboratories in quantities of a few atoms at a time.

A special property of period 7 is that the usual periodic repetition of chemical properties of the elements breaks down for the last elements of this period: Group 14 element ununquadium appears to be a noble gas instead of a poor metal, and group 18 element ununoctium probably is not a noble gas.^[1] This is due to relativistic effects appearing for very heavy atoms.

The period 7 elements are:

Chemical elements in the seventh period

Group	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18
# Name	87  Fr	88 Ra	89-103	104 Rf	105 Db	106 Sg	107 Bh	108 Hs	109 Mt	110 Ds	111 Rg	112 Uub	113 Uut	114 Uuq	115 Uup	116 Uuh	(117) (Uus)	118 Uuo
e--conf.
Actinides			89 Ac	90 Th	91 Pa	92 U	93 Np	94 Pu	95 Am	96 Cm	97 Bk	98 Cf	99 Es	100 Fm	101 Md	102 No	103 Lr
e--conf.

Element categories in the periodic table

Metals						Metalloids	Nonmetals			Unknown
Alkali metals	Alkaline earth metals	Inner transition elements		Transition elements	Other metals		Other nonmetals	Halogens	Noble gases
		Lanthanides	Actinides

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