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State at Standard Temperature and Pressure
 * Those lettered and numbered in  are gaseous
 * Those lettered and numbered in  are liquid
 * Those lettered and numbered in  are solid

Natural occurrence
 * Those with solid borders are primordial elements, which have stable isotopes older than the Earth
 * Those with dashed borders arise naturally from decay of other elements, and have no isotopes with a half-life comparable to the age of the Earth; however, some are found in trace amounts in radioactive ores
 * Those with dotted borders are synthetic elements, which do not occur naturally
 * Those without borders have not been discovered or synthesised yet