Thursday, November 29, 2007

The Elements

I've decided to continue to posts on chemistry, if only because I like them. They also lend themselves to a lot of pretty pictures. Anything which creates pretty pictures is golden on the internet.

Consider the following...

Sulfur:
Atomic Symbol: S
Atomic Number: 16
Almost anything that smells awful contains sulfur. Rotten eggs smell terrible because they contain hydrogen sulfide. Skunk odor is a mixture of three sulfur compounds, all of them noxious.
Sulfur is mentioned 15 times in the Bible, and was best known for destroying the cities of Sodom and Gomorrah. It was also known to the ancient Greeks, and appears in Homer's Odyssey. Small doses have been prescribed as a laxative for over 3000 years, which works because it acts as an irritant in the intestines.
Sulfur is found in some meteorites and there appears to be a deposit on the surface of the Moon. Io, one of the moons of Jupiter, is covered in sulfur spewed from its active volcanoes. It has been suggested that sulfur-using bacteria might live there, similar to types which survive in sulfur-rich environments on Earth.

Chlorine:
Atomic Symbol: Cl
Atomic Number: 17
Its ion Chlorde (Cl-) is essential to many species, including humans. The element itself, Chlorine gas, is very toxic, as its use as a weapon in World War I showed. Chlorine was first used as a weapon on 22 April, 1915. The German army released the gas from hundreds of cylinders, and the breeze carried the gas across no-man's land and into the British trenches. 5000 men died in agony, and 15000 were disabled by it. The threat was eventually countered by issuing gas masks.
The chlorination of drinking water has been common practice for almost a century. It virtually eliminates water-borne illnesses such as typhoid, cholera, and meningitis which were once common in overcrowded cities. Chlorination is cheap, safe, and effective at ridding water of disease pathogens.

Argon:
Atomic Symbol: Ar
Atomic Number: 18
Argon is one of a group of elements called the noble gases. Like them, it is an odorless, colorless gas; but unlike most of them, it is not rare. Roughly 1% of the atmosphere is composed of argon. Argon was first isolated in 1785 London, by the eccentric millionaire Henry Cavendish, who had a private laboratory. Perplexed by this small portion of the air which would not react chemically, he did not realize that it was a gaseous element, nor was he able to identify it using the primitive techniques of his day. The element remained "undiscovered" until 1904, by the winners of the Nobel prizes for chemistry and physics.
Argon turned out to be not as inert as had always been assumed. In August 2000, scientists at the University of Helsinki, Finland created the first ever compound of argon. Don't expect to see it turning up at the mall, though: this highly unstable substance had to be created and stored at temperatures under -265 oC.

My previous posts on chemistry are here.

Do you want to know more? Then check out Nature's Building Blocks, by John Emsley

No comments: