Editing Period 7 element (section)

==Properties==

All period 7 elements are [[radioactive]]. This period contains the [[actinides]], which include [[plutonium]], the last naturally occurring element;<ref>{{Cite web |title=Periodic Table – Royal Society of Chemistry |url=https://www.rsc.org/periodic-table/ |access-date=2023-10-19 |website=www.rsc.org}}</ref>{{refn | group = note | Trace quantities of <sup>239</sup>Pu are found in uranium deposits<ref>{{Cite book |last1=Miner |first1=William N. |title=The Encyclopedia of the Chemical Elements |last2=Schonfeld, Fred W. |publisher=Reinhold Book Corporation |year=1968 |editor-last=Clifford A. Hampel |location=New York (NY) |pages=[https://archive.org/details/encyclopediaofch00hamp/page/541 541] |chapter=Plutonium |lccn=68029938 |ref=CITEREFMiner1968 |chapter-url=https://archive.org/details/encyclopediaofch00hamp |chapter-url-access=registration}}</ref> due to [[neutron capture]] of {{sup|238}}U and subsequent [[beta decay]]. It is also possible that the long-lived isotope {{sup|244}}Pu [[Plutonium-244#Natural_occurrence|may exist primordially]].<ref>{{cite journal |last1=Wu |first1=Yang |last2=Dai |first2=Xiongxin |first3=Shan |last3=Xing |first4=Maoyi |last4=Luo |first5=Marcus |last5=Christl |first6=Hans-Arno |last6=Synal |first7=Shaochun |last7=Hou |date=2022 |title=Direct search for primordial {{sup|244}}Pu in Bayan Obo bastnaesite |url=http://www.ccspublishing.org.cn/article/doi/10.1016/j.cclet.2022.03.036?pageType=en |journal=Chinese Chemical Letters |volume=33 |issue=7 |pages=3522–3526 |doi=10.1016/j.cclet.2022.03.036 |access-date=29 January 2024|url-access=subscription }}</ref>}} subsequent elements must be created artificially. While the first five of these [[synthetic element]]s ([[americium]] through [[einsteinium]]) are now available in [[macroscopic]] quantities, most are extremely rare, having only been prepared in [[microgram]] amounts or less. The later [[transactinide]] elements have only been identified in laboratories in batches of a few atoms at a time.

Though the rarity of many of these elements means that experimental results are not many, their periodic and group trends are less well defined than other periods. Whilst [[francium]] and [[radium]] do show typical properties of their respective groups, [[actinides]] display a much greater variety of behavior and oxidation states than the [[lanthanides]]. These peculiarities are due to a variety of factors, including a large degree of [[spin–orbit coupling]] and relativistic effects, ultimately caused by the very high electric charge of their massive [[atomic nucleus|nuclei]]. Periodicity mostly holds throughout the 6d series and is predicted also for [[moscovium]] and [[livermorium]], but the other four 7p elements, [[nihonium]], [[flerovium]], [[tennessine]], and [[oganesson]], are predicted to have very different properties from those expected for their groups.