Polonium




 * Name: Polonium
 * Symbol: Po
 * Atomic number: 84
 * Atomic Weight: [ 209 ]
 * Standard State: solid at 298 K
 * Group: 16
 * Group Name: Chalcogen
 * Period: 6
 * Color: silvery
 * Classification: Metallic

Brief description: polonium has more isotopes than any other element, all of which are radioactive. Polonium dissolves readily in dilute acids, but is only slightly soluble in alkalies. Weight for weight it is about 2.5 x 1011 times as toxic as hydrocyanic acid (HCN). Polonium has been found in tobacco as a contaminant and in uranium ores.

Isolation: polonium is radioactive and excessively rare in nature. It is made in very small quantities through a nuclear reaction of bismuth. Neutron irradiation of 209bismuth (atomic number 83) gives 210polonium (atomic number 84). 209Bi + 1n → 210Po + e- Metallic polonium can be fractionally distilled from the bismuth or electrodeposited onto a metal surface such as silver.

Polonium A chemical element with the symbol **Po** and atomic number 84 discovered in 1898 by Marie Sklodowska-Curie and Pierre Curie. A rare and highly radioactive element with no stable isotopes, polonium is chemically similar to bismuth and tellurium, and it occurs in uranium ores. Applications of polonium are few, but include heating elements in spacecraft. The classification of polonium is disputed, with differing sources placing it as a post-transition metal and as a metalloid. Radioactive Polonium was discovered by Marie Sklodowska Curie, a Polish chemist, in 1898. She obtained polonium from pitchblende, a material that contains uranium, after noticing that unrefined pitchblende was more radioactive than the uranium that was separated from it. She reasoned that pitchblende must contain at least one other radioactive element. Curie needed to refine several tons of pitchblende in order to obtain tiny amounts of polonium and radium, another radioactive element discovered by Curie. One ton of uranium ore contains only about 100 micrograms (0.0001 grams) of polonium. Due to its scarcity, polonium is usually produced by bombarding bismuth-209 with neutrons in a nuclear reactor. This forms bismuth-210, which has a half-life of 5 days. Bismuth-210 decays into polonium-210 through beta decay. Milligram amounts of polonium-210 have been produced by this method. Polonium-210 is a very strong emitter of alpha particles. A single gram of polonium-210 creates 140 Watts of heat energy and is being considered as a lightweight heat source for thermoelectric power for spacecraft. Polonium-210 has a half-life of 138.39 days. Polonium's most stable isotope, polonium-209, has a half-life of 102 years. It decays into lead-205 through alpha decay. Polonium-209 is available from [|Oak Ridge National Laboratory] at the cost of about $3200 per microcurie. Polonium can be used to eliminate static electricity in machinery that is caused by processes such as the rolling of paper, wire or sheet metal, although other materials which emit beta particles are more commonly used for this purpose. Polonium is also used in brushes for removing dust from photographic films, although the polonium must be carefully sealed to protect the user from contamination. Polonium is also combined with beryllium to form neutron sources.
 * mixed or alloyed with beryllium to provide a source of neutrons
 * used for eliminating static charges in textile mills (β-sources are more common and less dangerous)
 * used on brushes for removing dust from photographic films
 * thermoelectric power in space satellites
 * source of neutrons
 * Atomic Number:** 84
 * Atomic Weight:** 209
 * Melting Point:** 527 K (254°C or 489°F)
 * Boiling Point:** 1235 K (962°C or 1764°F)
 * Density:** 9.32 grams per cubic centimeter
 * Phase at Room Temperature:** Solid
 * Element Classification:** Metal
 * Period Number:** 6 **Group Number:** 16 **Group Name:** Chalcogen
 * What's in a name?** Named for the country of Poland.
 * Say what?** Polonium is pronounced as **peh-LOW-nee-em**.
 * History and Uses:**
 * Estimated Crustal Abundance:** 2×10-10 milligrams per kilogram
 * Estimated Oceanic Abundance:** 1.5×10-14 milligrams per liter
 * Number of Stable Isotopes:** 0 (View all isotope data)
 * Ionization Energy:** 8.417 eV
 * Oxidation States:** +4, +2

Harmful effects: Polonium is harmful both through its chemical toxicity and its radioactivity. Polonium-210 is an alpha emitter. As such it is very hazardous if swallowed or inhaled. Exposure to polonium increases the risk of getting various cancers. Characteristics: Polonium is a rare, silvery-gray, radioactive low-melting metalloid. Polonium readily reacts with dilute acids, but only slightly with alkalis. All of its isotopes are radioactive. 210Po emits a blue glow, as the air around it is excited by the decay products. 1 gram of Po emits as many alpha particles as 5 kilograms of [|radium]. The energy released by polonium's alpha decay is considerable and heats the volume around it. The energy released is so large (140 W/g) that a capsule containing about half a gram reaches a temperature above 500 oC.

Uses of Polonium
Polonium is used to eliminate static electricity produced during processes such as rolling paper, wire and sheet metal. However, beta decay sources are more commonly used as they are less dangerous. 210Po can be used as an atomic heat source but because of the isotope's short half-life (138.4 days), it doesn't provide power for long-term uses. Polonium is also used in anti-static brushes to eliminate dust on photographic film. It is sealed in brushes to control the radioactive emissions.

A major source of where polonium can be found in would be uranium ores.


 * Symbol:** Po **Atomic Number:** 84 **Atomic Mass:** (209.0) amu **Melting Point:** 254.0 °C (527.15 K, 489.2 °F) **Boiling Point:** 962.0 °C (1235.15 K, 1763.6 °F) **Number of Protons/Electrons:** 84 **Number of Neutrons:** 125 **Classification:** Metalloid **Crystal Structure:** Monoclinic **Density @ 293 K:** 9.4 g/cm3 **Color:** Unknown

Atomic Structure

 * [[image:http://www.chemicalelements.com/bohr/b0084.gif width="355" height="353"]] ||  || **Number of Energy Levels:** 6
 * First Energy Level:** **Second Energy Level:** **Third Energy Level:** **Fourth Energy Level:** **Fifth Energy Level:** **Sixth Energy Level:** ||

Isotopes

 * ** Isotope ** || ** Half Life ** ||
 * Po-206 || 8.8 days ||
 * Po-207 || 5.8 hours ||
 * Po-208 || 2.89 years ||
 * Po-209 || 102.0 years ||
 * Po-210 || 138.38 days ||
 * Po-211 || 0.51 seconds ||
 * Po-212 || 0.29 microseconds ||
 * Po-213 || 4.0 microseconds ||
 * Po-214 || 163.7 microseconds ||
 * Po-215 || 1.78 milliseconds ||
 * Po-216 || 0.14 seconds ||
 * Po-218 || 3.1 minutes ||

Facts

 * Date of Discovery:** 1898 **Discoverer:** Pierre and Marie Curie **Name Origin:** After Poland **Uses:** No uses known **Obtained From:** pitchblende, decay of radium