Polonium
Symbol |
Name |
Atomic Number |
Atomic Weight |
Group Number |
Po |
Polonium |
84 |
(209) |
16 |
Standard Sate: solid at 298 K
Color: silvery
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 alkalis.
(PO), a radioactive, silvery-gray or black metallic element of the
oxygen family (Group VIa in the periodic table). The first element to
be discovered by radiochemical analysis, polonium was discovered in
1898 by Pierre and Marie Curie, who were investigating the
radioactivity of a certain pitchblende, a uranium ore. Polonium is a
very rare element (its abundance in the Earth's crust is about one part
in 1015) that occurs in nature as a radioactive decay product of
uranium, thorium, and actinium. The half-lives of its isotopes range
from a fraction of a second up to 103 years; the most common natural
isotope of polonium, polonium-210, has a half-life of 138.4 days.
Polonium usually is isolated from by-products of the extraction of
radium from uranium minerals. It can be produced artificially by
bombarding bismuth or lead with neutrons or with accelerated
charged particles.
Chemically, polonium resembles the elements tellurium and bismuth.
Because polonium is highly radioactive--it disintegrates to a stable
isotope of lead by emitting alpha rays, which are streams of positively
charged particles--it must be handled with extreme care. When
contained in such substances as gold foil, which prevent the alpha
radiation from escaping, polonium is used industrially to eliminate
static electricity generated by such processes as paper rolling, the
manufacture of sheet plastics, and the spinning of synthetic fibres. It
is also used on brushes for removing dust from photographic film and
in nuclear physics as a source of alpha radiation. Mixtures of
polonium with beryllium or other light elements are used as sources
of neutrons. atomic number 84 atomic weight 210 melting point 254
C (489 F) boiling point 962 C (1,764 F) density 9.4 g/cm3 oxidation
states -2, +2, +3(?), +4, +6 electronic config. 2-8-18-32-18-6 or
1s22s22p63s23p63d104s24p64d104f145s25p65d106s26p4
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