Group 16 ElementsBy Zach Bindell, Val Chin, & Kevin Pugh

Chalcogens

● Each element contains six valence electrons● Each element forms 2- ions● Located in the p block of the periodic table● The term chalcogen was first used by the

Wilhelm Blitz research group at the University of Hannover in Germany

Chalcogens● The term calcogen in greek is literally “copper

former” but can be translated to “ore former” or, more commonly, “chalk former”

● The characteristics of chalcogens vary dramatically because the group crosses the line between metals and nonmetals

● The elements are mostly solids at room temperature, excluding oxygen, which is a gas

Oxygen● Discovered in 1774 by Joseph Priestly in Wiltshire

England after he did experiments with HgO (mercuric oxide). He found out that by exposing the chemical to sunlight it liberated a gas that is now recognized as pure oxygen (O2).

● The name comes from the greek ‘oxy genes’ meaning ‘acid forming’.

● Oxygen is a diatomic element naturally found as a colorless, odorless gas. It is also highly flammable.

● It makes up 21% of the Earth’s atmosphere, 49% by mass of the Earth’s crust, and ⅔ of the human body.

● The oxygen content in the atmosphere is at the perfect concentration so organisms don’t die of asphyxiation or spontaneously combust.

● O16 is the most abundant isotope (99.762%)● Used in the production of a wide variety of chemicals

including nitric acid and hydrogen peroxide.● Used most commonly in the steel industry for welding

and cutting metal.

Sulfur■ General Characteristics

○ Assryian texts from 700-600B.C. state sulfur is a “product of the riverside” ○ Sulfur deposits were found along the rivers.○ Discovered in Northern Iraq

■ Physical Characteristics○ Solid at room temperature○ Nonmetal○ Yellow brittle crystals○ Density = 2.07g/cm3

○ Melting Point = 115.21oC, Boiling Point = 444.62oC■ Unique Facts

○ Used for organic insecticides, preservatives for dried fruits, and fertilizers○ Extracted from the Earth by Frasch processes.

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SULFUR

Selenium● Discovered in 1817 by Jöns Jacob Berzelius after

observing a red-brown sediment collected as a bi product of sulfuric acid.

● The name comes from ‘selene’ the Greek name for moon.

● Selenium is a metalloid naturally found in either a silvery metal or a red powder.

● It is an essential trace element in humans however in excess can act as a carcinogen.

● Most abundant isotopes: 80Se(49.6%), 78Se(23.7%), 76Se(9.4%).

● Used as an additive to glass to make it clear.● Used in photocells, solar cells, and photocopiers

because it is useful in converting light energy to electrical energy.

Tellurium■ General Characteristics

○ Discovered by Franz Joseph Miller von Reichstein in Romania, 1783○ Found in gold ores○ He was intrigued by the metallic sheen in gold ore and discovered Tellurium

■ Physical Characteristics○ Solid at room temperature○ Grey powder○ Density = 6.232g/cm3

○ Melting Point = 449.51oC, Boiling Point = 988oC■ Unique Facts

○ Used with copper and stainless steel to improve machinability○ Very toxic metalloid○ If workers mining Tellurium are exposed to tellurium, they get “tellurium breath”

that smells like garlic breath.

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TELLURIUM

Polonium-Po● Named for the country of Poland, where it was discovered● A silvery grey radioactive semimetal which is a solid at room

temperature● Melting point: 254°C, 489°F● Boiling point: 962°C, 1764°F● Density: 9.32 g/cm3

● Used as an alpha emitter● Used as a source of heat in space equipment● Very rare natural element● Mendeleev predicted Po would exist because of a missing space

on his periodic table● In 1898 Marie Curie and husband Pierre extracted some Polonium

from pitchblende (uranium oxide, U3O8)