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KRYPTON
by Aidan Emory
Symbol – Kr Atomic Number 36
HISTORICAL BACKGROUND
Krypton was discovered on May 30, 1898 by a Scottish chemist and physicist Sir William Ramsey and his assistant English chemist Morris William Travers in London, England. There were missing noble gases as the periodic table contained empty boxes between helium and argon. Ramsey and Travers thought that the missing elements could be gases and could be found in air.
They discovered the gas by allowing liquid air to evaporate. Then it becomes liquid by cooling it. The colder the air becomes the more gases within it turn into liquids. When it evaporated the gas was discovered as the normal air boiled off. The worked involved in discovering krypton was a very difficult task as it is not abundant in air. For every 100 liters of air, there is only about one-tenth of a milliliter of krypton. The name krypton came from the Greek word kryptos meaning hidden.
PHYSICAL PROPERTIES
- Krypton is a colorless, odorless, and tasteless gas.
- 2155 kg m-3 Density @ 293 K: 3.74 g/cm3 (Low density as atoms are very far apart.)
- Melting Point – 115.79 (or – 157.36 C and -251.25 F
- Boiling Point - 119.93 [or -153.22 °C (-243.8 °F)] K
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- Abundance – Krypton is found in the atmosphere and is approximately 0.000108 to 0.000114 percent. The element is also formed in the earth’s crust when uranium and other radioactive elements break down. The amount in the earth is too small estimate the amount. Abundances of the element in different environments:
% in Universe 4×10-6%
% in Sun N/A
% in Meteorites N/A
% in Earth's Crust 1.5×10-8%
% in Oceans 2.1×10-8%
% in Humans N/A
CHEMICAL PROPERTIES
- Electro Negativity – Krypton on the Pauling scale is 3.00.
- Ionization Energy – 1st IP (energy to remove 1st electron is 1350.8 kJ-mol-1. 2nd IP (energy to move the 2nd electron is 2350.4 kJ-mol-1.
- Reaction Partners
- Krypton does not react with water, however, is does dissolve slightly.
- When a mixture of krypton and fluorine, F2, is cooled to -196 degrees C and zapped with an electric discharge or x-rays, the result is the formation of difluoride-krypton II. This compound decomposes when warmed to room temperature.
- Other halogens do not react with krypton.
- Krypton does not react with any acids or bases.
PHOTOGRAPHS
ELECTRON CONFIGURATION AND LEWIS DOT STRUCTURE
Electron Configuration
- 1s22s22p63s23p63d104s24p6
- Abbreviated: [Ar]3d104s24p6
Lewis Dot Structure
ELEMENT BLOCK
- Krypton is a noble gas and refers to elements in Group 18 and Period 4 of the periodic table.
- Krypton is also referred to as an inert gas which means inactive.
SOURCE
"Krypton." Chemicool Periodic Table. Chemicool.com. October 17 2012. Web. 10/29/2012.
“Chemical Elements: From Carbon to Krypton,” Chemistry Explained. Gale.com. Web. 10/28/2012
Naik, Abhijit. “Facts about Noble Gases”. Buzzle.com. March 23, 2011. Web. 10/29/2012
Asimov, Isaac. The Noble Gases. New York:Basic Books, 1966 First Edition.
Moore, John T. Chemistry for Dummies Indianapolis: John Wiley & Sons, Inc. June 2011
BOHR MODEL
