Actinium

Actinium is the first of the actinide series of elements. They are a separate set because the behavior of actinium was so similar to the rare earth elements, particularly lanthanum.

Actinium is very active, actually 150 times more so than radium. None of it's properties are stable. It was discovered by Andre Debierne in 1899 and is named from the Greek word for beam/ray.

Actinium is found in decaying uranium and can be prepared by reducing flouride within lithium vapor. Because of it's high activity level, it is good at producing neutrons but more importantly, it has been used in studies to help cure cancer.

Francium

Discovered by Marguerite Perey of France in 1939, francium was named for France. The isotopes of francium are highly unstable, so all information known about it is from radiochemical techniques. It occurs naturally in uranium, but less than one ounce can be in the earth's crust at one time. Francium was actually predicted in 1870- scientists were convinced that there would be another alkali metal higher than caesium. They even predicted it would be element number 87!

There had been numerous false claims to the discovery of francium, but Marguerite was the one to discover it. The difference between her and other researchers is that she found the traces of it in decaying actinium; actinium is the PRIMARY natural source of francium, but it is harder to obtain than from uranium. Due to its rarity, francium has not been used in any commercial products or machines.

Radon

Discovered by Fredrich Ernst Dorn of Germany in 1898, radon was originally called radium emanation. It was isolated in 1908 and named niton. It's name originates from the word radium. It is a heavy radioactive gas, and it is colorless at regular temperatures. It is the heaviest of all gases. At very cold temperatures it appears yellow. Inhalation of radon is very bad, and in fact it has been tested and radon is the second leading cause of cancer.

Radon occurs naturally in some spring waters. Ernest Rutherford is sometimes mistakenly credited with the discovery of radon... however, he discovered the alpha particle radiation given OFF by radon.

Astatine

Astatine is the 85th element. Discovered in 1940 by Dale Corson, Kenneth McKenzie and Emilio Segre, it was once believed to be the rarest element on Earth. Astatine isn't the RAREST, but it is among the rare elements of Earth, as it is usually found in part of a larger element that is in radioactive decay. Only up to one gram of astatine is found in nature at a time.

Astatine is invisible with the naked eye, since a sample large enough to see would disintegrate from its own radioactivity. Because of this, it is estimated that there can only be TWENTY-EIGHT GRAMS OF ASTATINE ON EARTH AT A TIME. Astatine is an important element in nuclear medicine, but as it decays so quickly it must be used within a few hours of its production. It has been used instead of iodine in some procedures, safer as it has a shorter half-life.

Bismuth

Not a lot is known about bismuth- but it is quite possibly one of the prettiest elements I have done so far. It is a very brittle, crystalline, silver metal with a multicolored tinge to it. It is the most naturally diamagnetic metal- this means that it is repelled by the magnetic field.

It also has a high electrical resistance... in fact, it's thermal conductivity is the lowest of any metal, excusing mercury. Like water, when it is frozen it expands.

Bismuth is often used in:

• Medicine (bismuth subnitrate)
• Cosmetics
• Fire detectors and extinguishers
• Bismuth/tin alloy (replacement for lead in bullets.)