Editing Period 6 element (section)

===Lead===
{{main|Lead}}
'''Lead''' is a main-group [[Chemical element|element]] in the [[carbon group]] with the symbol '''Pb''' (from {{langx|la|plumbum}}) and [[atomic number]] 82. Lead is a soft, [[malleable]] [[other metal]]. It is also counted as one of the [[heavy metal (chemistry)|heavy metal]]s. Metallic lead has a bluish-white color after being freshly cut, but it soon tarnishes to a dull grayish color when exposed to air. Lead has a shiny chrome-silver luster when it is melted into a liquid.

Lead is used in building construction, [[lead–acid battery|lead-acid batteries]], [[bullet]]s and [[lead shot|shot]]s, weights, as part of [[solder]]s, [[pewter]]s, [[fusible alloy]]s and as a [[radiation shield]]. Lead has the highest [[atomic number]] of all of the [[stable element]]s, although the next higher element, [[bismuth]], has a [[half-life]] that is so long (much longer than the age of the universe) that it can be considered stable. Its four stable isotopes have 82 [[proton]]s, a [[magic number (physics)|magic number]] in the [[nuclear shell model]] of [[atomic nuclei]].

Lead, at certain exposure levels, is a poisonous substance to animals as well as for human beings. It damages the [[nervous system]] and causes [[brain]] disorders. Excessive lead also causes blood disorders in mammals. Like the element [[mercury (element)|mercury]], another heavy metal, lead is a [[neurotoxin]] that accumulates both in soft tissues and the bones. [[Lead poisoning]] has been documented from [[ancient Rome]], [[ancient Greece]], and [[History of China#Ancient China|ancient China]].