Period 6 element 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 ancient China. Bismuth is a chemical element with symbol Bi and atomic number 83. Bismuth, a trivalent other metal, chemically resembles arsenic and antimony. Elemental bismuth may occur naturally uncombined, although its sulfide and oxide form important commercial ores. The free element is 86% as dense as lead. It is a brittle metal with a silvery white color when newly made, but often seen in air with a pink tinge owing to the surface
Hard and soft C Hard and soft C In the Latin-based orthographies of many European languages (including English), a distinction between hard and soft occurs in which represents two distinct phonemes. The sound of a hard (which often precedes the non-front vowels , and ) is that of the voiceless velar stop, (as in "car") while the sound of a soft (typically before , and ), depending on language, may be a fricative or affricate. In English, the sound of soft is (as in "citrus"). There was no soft in classical Latin, where it was always pronounced as . Modern English pronunciation of early