Friday, March 20, 2020

Polonium Facts - Element 84 or Po

Polonium Facts - Element 84 or Po Polonium (Po or Element 84) is one of the radioactive elements discovered by Marie and Pierre Curie. This rare element has no stable isotopes. Its found in uranium ores and cigarette smoke and also occurs as a decay product of heavier elements. Although there arent many applications for the element, it is used to generate heat from radioactive decay for space probes. The element is used as a neutron and alpha source and in anti-static devices. Polonium has also been used as a poison to commit assassinations. Although the position of element 84 on the periodic table would lead to categorization as a metalloid, its properties are those of a true metal. PoloniumBasic Facts Symbol: Po Atomic Number: 84 Discovery: Curie 1898 Atomic weight: [208.9824] Electron configuration: [Xe] 4f14 5d10 6s2 6p4 Classification: semi-metal Ground level: 3P2 Polonium Physical Data Ionization potential: 8.414 ev Physical form: Silvery metal Melting point: 254Â °C Boiling point: 962Â °C Density: 9.20 g/cm3 Valence: 2, 4 References: Los Alamos National Laboratory (2001), Crescent Chemical Company (2001), Langes Handbook of Chemistry (1952), CRC (2006)

Wednesday, March 4, 2020

Geography of Ancient Greece

Geography of Ancient Greece Greece, a country in southeastern Europe whose peninsula extends from the Balkans into the Mediterranean Sea, is mountainous, with many gulfs and bays. Forests fill some areas of Greece. Much of Greece is stony and suitable only for pasturage, but other areas are suitable for growing wheat, barley, citrus, dates, and olives. It is convenient to divide ancient Greece into 3 geographical regions (plus islands and colonies): (1) Northern Greece,(2) Central Greece(3) The Peloponnese.​ I. Northern Greece Northern Greece consists of Epirus and Thessaly, separated by the Pindus mountain range. The chief town in Epirus is Dodona where the Greeks thought Zeus provided oracles. Thessaly is the largest plains area in Greece. It is almost surrounded by mountains. On the north, the Cambunian range has as its highest mountain the home of the gods, Mt. Olympus, and nearby, Mt Ossa. Between these two mountains is a valley called the Vale of Tempe through which runs the Peneius River. II. Central Greece Central Greece has more mountains than northern Greece. It contains the countries of Aetolia (famed for the Calydonian boar hunt), Locris (divided into 2 sections by Doris and Phocis), Acarnania (west of Aetolia, bordered by the Achelous River, and north of the Gulf of Calydon), Doris, Phocis, Boeotia, Attica, and Megaris. Boeotia and Attica are separated by Mt. Cithaeron. In northeast Attica is Mt. Pentelicus home of the famous marble. South of Pentelicus is the Hymettus mountain range, which is famous for its honey. Attica had poor soil, but a long coastline favoring trade. Megaris lies in the Isthmus of Corinth, which separates central Greece from the Peloponnese. The Megarans raised sheep and made woolen products and pottery. III. Peloponnesus South of the Isthmus of Corinth is the Peloponnese (21,549 sq. km), whose central region is Arcadia, which is a plateau over mountain ranges. On the northern slope is Achaea, with Elis and Corinth on either side. On the east of the Peloponnese is the mountainous Argolis area. Laconia was the country in the basin of the Eurotas River, which ran between the Taygetus and Parnon mountain regions. Messenia lies to the west of Mt. Taygetus, the highest point in the Peloponnese. Source: An Ancient History for Beginners, by George Willis Botsford, New York: Macmillan Company. 1917.