Editing Period 6 element (section)

==Properties==
This period contains the [[lanthanides]], also known as the ''rare earths''. Many lanthanides are known for their magnetic properties, such as [[neodymium]]. Many period 6 [[transition metals]] are very valuable, such as [[gold]], however many period 6 [[other metals]] are incredibly toxic, such as [[thallium]]. Period 6 contains the last stable element, [[lead]]. All subsequent elements in the periodic table are [[radioactive]]. After [[bismuth]], which has a half-life or more than 10<sup>19</sup> years, [[polonium]], [[astatine]], and [[radon]] are some of the [[Half-life|shortest-lived]] and rarest elements known; less than a gram of astatine is estimated to exist on earth at any given time.<ref name="Gray" >{{cite book|last=Gray|first=Theodore|title=The Elements: A Visual Exploration of Every Known Atom in the Universe|year=2009|publisher=Black Dog & Leventhal Publishers|location=New York|isbn=978-1-57912-814-2|url-access=registration|url=https://archive.org/details/elementsvisualex0000gray}}</ref>