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Chalcogens. By: Justin, Josh and Kayla. History/Discovery. Chalcogens are also known as the Oxygen Family The Oxygen Family consists of non metals and metalloids There are 5 elements in the Oxygen Family which are Oxygen, Sulfur, Selenium, Tellurium and Polonium. History/Discovery.
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Chalcogens By: Justin, Josh and Kayla
History/Discovery • Chalcogens are also known as the Oxygen Family • The Oxygen Family consists of non metals and metalloids • There are 5 elements in the Oxygen Family which are Oxygen, Sulfur, Selenium, Tellurium and Polonium
History/Discovery • Joseph Priestley is generally credited with the discovery who made oxygen by heating lead or mercury oxides, but Carl Scheele also reported it independently. • Sulphur is one of the elements which has an alchemical symbol • Selenium was first reported to be Tellurium before they identified it as Selenium • Polonium was the first element discovered by Marie Curie in 1898, while seeking the cause of radioactivity of pitchblende from Bohemia
Common Reactions • At ordinary temperatures and pressures, oxygen is a gas. It exists in either of two allotropic forms: O2, which makes up 21 percent of the earth’s atmosphere, or O3 (ozone), which slowly decomposes to O2. O3 can be prepared by passing an electrical discharge through O2 or air:
Common Reactions • This reaction occurs naturally as a result of lightning bolts. O3 is also produced by any device which produces electrical sparks. You may have noticed its distinctive odor in the vicinity of an electric motor, for example. • Oxygen 2H2O2(l) → 2H2O(l) + O2(g) • Sulfur S8(s) + 8O2(g) → 8SO2(g)
Everyday Common use • Common uses for the Oxygen Family are : • Used in making methanol and ethene oxide • Rocket fuel oxidant • Steel manufacture • Breathing • Used to produce sulphuric acid, H2SO4 • Used in batteries ("battery acid") • Used in photocopying for reproducing and copying documents, letters, etc.
Physical Properties • Oxygen – Low density, Melting point: 54.36 K, -218.79 °C, Boiling point: 90.20 K, -182.95 °C, phase: gas • Sulfur – High density, Melting point: 388.36 K, 115.21 °C, Boiling point: 717.8 K, 444.6 °C, phase: solid • Selenium – High density, Melting point: 494 K, 221 °C, Boiling point: 958 K, 685 °C, phase: solid • Tellurium – High density, Melting point: 722.66 K, 449.51 °C, Boiling point: 1261 K, 988 °C, phase: solid • Polonium – High density, Melting point: 527 K, 254 °C, Boiling point: 1235 K, 962 °C, phase: solid
Properties of the atoms • How many valence electrons are in the Oxygen Family? • There are 6, valence electrons in the Oxygen Family. • What is the radius of the Oxygen Family? • Atomic (pm): 605 • Ionic (pm):743 • How much Ionization is in the Oxygen Family? • There is 4936(kj/mol)