Co Kobalt 27 58.933195 9 4 d 27 1495.0 2870.0 [Ar] 3d7 4s2 2 8 15 2 8.9 0.003% Gray Hexagonal 1.9 1.84 {"1":"760.4","2":"1648","3":"3232","4":"4950","5":"7670","6":"9840","7":"12440","8":"15230","9":"17959","10":"26570","11":"29400","12":"32400","13":"36600","14":"39700","15":"42800","16":"49396","17":"52737","18":"134810","19":"145170","20":"154700","21":"167400","22":"178100","23":"189300","24":"204500","25":"214100","26":"920870","27":"966023"} 761 63.7 126 +2,3 1.25 6.7 16.19 373.3 0.421 100.0 0 Solid, Ferromagnetic, Conductor, TransitionMetal, Metal, Stable, Natural KO-bolt Hard, ductile, lustrous bluish-gray metal. Exists in the earth's curst in cocentrations of about 25 ppm. It has remarkable magnetic properties. Used in many hard alloys; for magnets, ceramics and special glasses. Remains hard up to 982°C. Radioactive cobalt-60 is used in cancer therapy. Occurs in compounds with arsenic, oxygen and sulfur as in cobaltine (CoAsS) and linneite (Co3S4). Pure cobalt is obtained as a byproduct of refining nickel, copper and iron. V6ljxByu9ng Cobalt

Oko 1630., belgijski kemičar i liječnik Jan Baptist van Helmont raspoznao je klor kao plin.

Elementarni klor je po prvi put pripremio i proučavao švedski kemičar Carl Wilhelm Scheele 1774.

Do 1810., znanstveni konsenzus je bio da je klor spoj koji sadrži kisik.

1811., Sir Humphry Davy je zaključio da je klor novi element. Od grčke riječi chloro, zelenkasto žuta 27 1735 Georg Brandt Sweden From the German word "kobald" meaning "goblin" or evil spirit

Elemental chlorine at high concentrations is extremely dangerous and poisonous

Tree frogs have a chlorine compound in their skin that is a very powerful pain killer

Chlorine is used for producing safe drinking water.

It is also extensively used in the production of paper products, dyestuffs, textiles, petroleum products, medicines, antiseptics, insecticides, food, solvents, paints, plastics, and many other consumer products.

Chlorinated compounds are used mostly for sanitation, pulp bleaching, disinfectants, and textile processing.