Polonium

Polonium
General Info
Atomic Symbol	Atomic symbol::Po
Atomic Number	Atomic number::84
Atomic Weight	Atomic weight::209 g/mol
Chemical series	metalloid
Appearance	Metallic
Group, Period, Block	16, 6,
Electron configuration	[Xe] 6s2, 4f14, 5d10, 6p4
Electrons per shell	2, 8, 18, 32, 18, 6
CAS number	CAS number::7440-08-6
Physical properties
Phase	solid
Density	Density::9.4 g/ml
Melting point	Melting point::254 °C
Boiling point	Boiling point::962 °C
Isotopes of Polonium
iso NA half-life DT DE (MeV) DP 208Po syn 2.898 y α 5.215 204Pb 208Po syn 2.898y ε,β+ 1.401 208Bi 209Po syn 102 y α 4.979 205Pb 209Po syn 102 y ε,β+ 1.893 209Bi 210Po trace 138.38 d α 5.307 206Pb
All properties are for STP unless otherwise stated.

Polonium is a chemical element that is part of the metalloids group in the periodic table of elements. Its atomic number is 84 and its symbol is Po. It was first discovered in 1898 when Madam Curie investigated the cause of radiation emitting from pitchblende ore from Joachimsthal, Bohemia. The electroscope showed its seperation from bismuth, and Madam Curie named the new element after her home country: Poland. It is infrequently referred to as radium-F. It is both highly radioactive and very rare.

Properties

Polonium is a metallic substance with a silvery gray color. It is also a radioactive metalloid with a low melting point. Polonium is very soluble in dilute acids and slightly soluble in alkali acids. Also, when mixed or alloyed with Beryillium, it provides a source of neutrons as a result.

Polonium has 33 known isotopes, ranging from ¹⁸⁸Po to ²²⁰Po. All of these isotopes are radioactive but ²⁰⁸Po, ²⁰⁹Po, and ²¹⁰Po are the only isotopes that have half lives that are practical for observation and use. ²¹⁰Po is the most common and most used isotope of polonium with a half life of 138 days. It is an alpha emitting element and is highly radioactive. It has a 140 W/g decay rate and one milligram of ²¹⁰Po gives off as many alpha particles as 5 grams of radium. Half a gram of ²¹⁰Po will reach temperatures over 500°C. Due to its high energy discharge, ²¹⁰Po has a blue-colored glow due to the excitation of the gas around it. It is somewhat volatile, as 50% of it will become airborne over a course of 45 hours when it is heated to 55 °C.

Occurrences

Polonium is a very rate element. It is found naturally in uranium ores, but only in very small quantities. It is also found naturally in the soil in very small concentrations, where there is about a one trillionth curie per gram concentration. It is also found in uranium ore, with about 0.1 mg of Polonium-210 per ton of uranium ore. ²¹⁰Po can also be found in pitchblade ore and is present in aged radium salts with a concentration of 0.2 mg of ²¹⁰Po per gram of radium. Other isotopes of polonium are found naturally in nature, but their short half lives keep them from being found in adequate concentrations.

Polonium isotopes are very rare, and as a result they are usually produced artificially. ²¹⁰Po can be produced by firing neutrons at bismuth-209 using nuclear reactors in order to make bismuth-210. ²¹⁰Bi has a half life of five days, and will become ²¹⁰Po through beta decay. Through this process, milligrams of Po-210 are formed. Polonium-209 and polonium-208 can be artificially formed using reactors or particle accelerators, but these are much more expensive to make. Oak Ridge National Laboratory sells polonium-209 commercially at a cost of $3195/microcurie (a commonly-used measure of radioactivity).

Uses

Polonium-210 is the only isotope of polonium that has any real use. It is most commonly found in static eliminators, machines that eliminate static electricity. Static eliminators are used in other machines that create items in a manner that produces static electricity. Paper rolling, manufacturing sheet plastics, and spinning synthetic fibers are a few examples. The isotope's alpha particles are used to ionize the air which then neutralizes the static electricity. The isotope usually needs to be changed out every year because of its short half life and isotopes emitting beta particles are more commonly used as they are safer to use. Polonium-210 is also used in brushes that remove dust from photographs and camera lenses, and can be used as an atomic heat source. As stated earlier, it can be combined with beryllium to produce neutrons. This technique was used in the first generation of atomic weapons. Polonium-210 is also used as a thermoelectric power source for space satellites.

Effects to Health

Due to its high levels of radioactivity, Polonium-210 is a highly dangerous element. When it is used, the specific equipment is used to contain the radioactive element, and the most strict procedures are followed. The maximum threshold for the human body is 0.03 microcuries of polonium-210. It is about 2.5 x 10¹¹ times as toxic as hydrocyanic acid. It is not dangerous unless ingested though, and a particle of Polonium enters the tissue of the human body. This can happen through drinking water with polonium, or eating food grown in soil with concentrations of polonium. Most of these do not result in danger to the body since polonium occurs naturally in the soil in low concentrations and since the digestive system effectively reduces the risk of death. The most dangerous form of exposure to Polonium is inhaling air that has polonium particles on it, as the lungs have no way of resisting the radioactivity of the element. This usually occurs with people who work in factories that use Polonium.

Polonium Halos

Main Article: Pleochroic halos

Polonium halos, or radiohalos as they are sometimes called, are small circles of color found in granite and are caused by the rapid decay of polonium-210. Ever since Robert V. Gentry discovered these small colorful circles back in the late 70s, there has been great debate in the scientific community between creationists and evolutionists on the significance of these halos.

Robert Gentry viewed Polonium halos as evidence for a young earth. Polonium halos are formed by the rapid decay of ²¹⁰Po when it is embedded in granite. Since polonium-210 has a very short half life, the granite it is formed in would have had to be melted and cooled within days or the rings would not have been able to form. This is very different from the evolutionists' belief that it took the sea of primordial matter years to form. Gentry believed that this proves the earth was made instantaneously and was not formed over millions of years. Many evolutionists disagree, but he claims that his theory has yet to be refuted.

Creation Ministries International has shown that Gentry's experimentation and results are correct, but they have a different conclusion than Gentry's. They reasoned that in order to produce such small circles of polonium, a polonium source would have to be nearby. Through experimentation, it was discovered that polonium halos are able to form when hot water carries polonium through granite. This results in the distribution of polonium, and shows how polonium halos could have first formed. Through this evidence, Creation Ministries suggests that the polonium halos were distributed through the world wide flood that occurred in Noah's time.