~ #27
by Sasha 8th Grade, Mill Valley Middle School |
||||||||||||||||||||||||||||||||
|
"If your glass turns blue, it's not your fault - blame cobalt salts!"
|
||||||||||||||||||||||||||||||||
|
|
•
Properties |
|
||||||||||||||||||||||||||||||
|
||||||||||||||||||||||||||||||||
|
As a
transition metal, cobalt is ductile
and mallaeble,
and has the ability to conduct electricity and heat. Cobalt,
along with only two other elements, iron and nickel, can
produce a magnetic field. Cobalt's Curie
point,
at 1121º C, is the highest of any known metal. Its
valence electrons are not only located in the outer shell,
but others as well, which is why so many isotopes
can be found (see table below). Cobalt is a hard and brittle
metal, which is a silvery-white unless polished, when it
becomes a slight blue color. Cobalt salts can turn glass a
beautiful blue shade. Isotope Co-53 Co-54 Co-55 Co-56 Co-57 Co-58 Co-59 Co-60 Co-61 Co-62 Co-63 Co-64 260
ms 190
ms 17.5
hrs 77.3
days 271.8
days 70.9
days 5.3
yrs 1.7
hrs 1.5
mins 27.5
sec 300
ms |
||||||||||||||||||||||||||||||||
|
Cobalt was discovered circa 1730 by Swedish chemist George Brandt. He was the first to isolate cobalt from a similar element, bismuth, which people had given the credit if cobalt's blue coloring to. However, we have been aware of cobalt's existance for centuries. 
..................... Even ancient civilizations were aware of the coloring effect cobalt compunds could hav on glass. by the 16th century, chemists were referring to this mineral as "zaffer." German miners would call it "kobald," or a legendary imp believed to cause the difficulties of mining, when frustrated. by the 18th century, the element was known as cobalt. |
||||||||||||||||||||||||||||||||
|
One fourth of the worl'd cobalt production is used for making powerful magnet alloys known as "alcino," which are made of aluminum, nickel, and cobalt. It is also an important contribution to steel alloys. some radioactive isotopes of cobalt are a valuable radiation source and can be used as medical equiptment. Cobalt-60, ith its long half-life period of 5.3 years, is a valuable source of radiation, and is sometimes used in place of X-ray to find errors inside products and materials. |
||||||||||||||||||||||||||||||||
|
Alloys - a type of mixture composed of metals Curie point - the temperature at which an element loses its ability to conudct a magnetic field Ductile - can be drawn into thin wires Electrons - the negatively charged particles found outside the atom's nucleus. Electrons have an extremely small, insignificant, mass. Element family - Elements are organized into families, or columns on the periodic table, according to their number of valence electrons, or number of electrons in their outer shell Element period - Elements are organized into periods, or rows on the periodic table, according to their properties Half-Life period - the amount of time it takes for an isotope to wear down to half its radioactive potential Isotopes - an atom of an element which has the same number of protons and electrons as others, but a different number of neutrons. An element's weight, measured in AMU, or atomic mass unit, is an average of all its known isotopes. Malleable - can be shaped into very thin material Neutrons - the neutral particles (with no charge) found in the atom's nucleus. Neutrons have a mas of one AMU. Oxidation state - the number of elelectrons that an element gives, receives, or shares when it reacts with another element Protons - the positively charged particles found in an atom's nucleus. Protons have a mass of one AMU. Stable - an isotope that is not radioactive |
||||||||||||||||||||||||||||||||
|
Heiserman, David L. Exploring Chemical Elements and Their Compounds. TAB Books: Blue Ridge Summit, Pa 1992. Todd, Robert W., Ed. Holt Science & Technology: Physical Science. Holt, Rinehart, And Winston: Austin, Texas, 2001 Magnet Animation Provided by: Animation Factory Title Animation Provided by: Flaming Text |
||||||||||||||||||||||||||||||||
