Heavy metals are metals with relatively high densities, atomic weights, or atomic numbers, depending on the context. They are usually the denser metals in metallurgy, or the metals with higher atomic numbers in physics, whereas chemists distinguish heavy metals by their chemical behaviour. Heavy metals tend to be less chemically reactive than light metals such as sodium, magnesium, and aluminium. The earliest known metals are heavy metals, including common metals such as iron, copper, and tin, and precious metals such as silver, gold, and platinum. Less familiar metals such as gallium, hafnium, and thallium are also heavy metals, as are the essential nutrients iron, cobalt, and zinc. Some are toxic in larger amounts or certain forms (silver and indium, for example); others, like cadmium, mercury, and lead, are highly poisonous. Sources of heavy metal poisoning may include mining and industrial waste, agricultural runoff, occupational exposure, paints and treated timber. Heavy metals are relatively scarce in the Earth's crust, but are present in many manufactured products.
Read more: https://en.wikipedia.org/wiki/Heavy_metals
_______________________________ Today's selected anniversaries:
1002:
King Æthelred II ordered the massacre of all Danes in England. https://en.wikipedia.org/wiki/St._Brice%27s_Day_massacre
1841:
Scottish surgeon James Braid observed a demonstration of animal magnetism, which inspired him to study the subject he eventually called hypnotism. https://en.wikipedia.org/wiki/James_Braid_(surgeon)
1927:
The Holland Tunnel, connecting New York City's Manhattan with Jersey City, New Jersey, under the Hudson River, opened. https://en.wikipedia.org/wiki/Holland_Tunnel
1966:
The Israeli military conducted a large cross-border assault on the Jordanian-controlled West Bank village of Samu in response to an al- Fatah land mine incident two days earlier near the West Bank border. https://en.wikipedia.org/wiki/Samu_Incident
1982:
South Korean boxer Kim Duk-koo suffered fatal brain injuries during a match with American Ray Mancini near Las Vegas' Caesars Palace, leading to significant rule changes in the sport. https://en.wikipedia.org/wiki/Kim_Duk-koo
_____________________________ Wiktionary's word of the day:
spoils of war: Any profits extracted as the result of winning a war or other military activity. https://en.wiktionary.org/wiki/spoils_of_war
___________________________ Wikiquote quote of the day:
It was pride that changed angels into devils; it is humility that makes men as angels. --Augustine of Hippo https://en.wikiquote.org/wiki/Augustine_of_Hippo