Chapter 21 The Chemistry of the Main Group Elements Key Terms
Periodic table- the periodic table is a very useful tool in chemistry that
organizes elements so they are arranged so that those with similar chemical and
physical properties lie in vertical columns called groups or families. The
periodic table also has horizontal rows called periods, which are number.
Element abundance- element abundance is the quantity of an element that occurs naturally on earth.
Electro negativity- A measure of the ability of an atom in a molecule to attract electrons to itself
Metallic character- Chemical properties associated with those elements classed as metals. These properties, which arise from the element’s ability to lose electrons, are: the displacement of hydrogen from dilute acids; the formation of basic oxides; the formation of ionic chlorides; and their reducing reaction
Hydrogen- the first element on the periodic table
consisting of one proton and one electron. Hydrogen is also the most abundant
element in the universe.
Haber process- the direct, catalyzed combination of gaseous nitrogen and hydrogen to produce ammonia
Alkali metals- the metals in Group 1A of the periodic table
Alkaline earth metals- the elements in group 2A of the periodic table
Hall-Heroult process- the chemical process of refining aluminum into its elemental form by using molten cryolite to first dissolve alumina, and then by running a powerful DC current through this solution to retrieve metallic aluminum
Aluminum- Pure aluminium is a silvery-white metal with many desirable characteristics. It is light, nontoxic (as the metal), nonmagnetic and nonsparking. Aluminum is an abundant element in the earth's crust, but it is not found free in nature.
Silicon- Silicon is present in the sun and stars and is a principal component of a class of meteorites known as aerolites. Silicon makes up 25.7% of the earth's crust by weight, and is the second most abundant element, exceeded only by oxygen. It is found largely as silicon oxides such as sand (silica), quartz, rock crystal, amethyst, agate, flint, jasper and opal.
Silicates are compounds of
Silicon and Oxygen combined with one or more metal ions. Since Silicon and
Oxygen together make up almost 75% of the earth's crust, Silicates are by far
the most commonly found minerals
Zeolites- Zeolites are microporous crystalline solids with well-defined structures. Generally they contain silicon, aluminum and oxygen in their framework and cations, water and/or other molecules within their pores.
Nitrogen and Phosphorus- Nitrogen is found primarily as N2
in the atmosphere, where it constitutes 78.1% by volume, while phosphorus occurs
in Earth’s crust as solids. Nitrogen and its compounds play a key role in our
economy, with ammonia being particularly notable. Phosphoric acid is an
important commodity chemical, its major use being in fertilizers. Both
Phosphorus and nitrogen are part of every living organism. These two elemtns are
both in the 5A family.
Ostwald process- The Ostwald process is a commercial process, invented by Wilhelm Ostwald used to produce nitric acid. ammonia is heated with a catalyst (platium) to form nitric oxide that is then oxidizedto yield nitrogen dioxide, which in turn reacts with water to yield nitric acid and nitric oxide.
Oxygen and Sulfur- Oxygen is by far the most abundant element in the Earth’s crust, presenting just under 50% of its weight. It is present as elemental oxygen in the atmosphe, and is combined with other elements in water and in many minerals. Sulfur is the 15th most abundant element in the Earth’s crust. It is found in elemental form only in certain concentrated deposits. Sulfur containing compounds occur in natural gas and oil Both of these elements are in the 6A family.
Frasch process- Process used to extract underground deposits of sulphur. Superheated steam is piped into the sulphur deposit and melts it. Compressed air is then pumped down to force the molten sulphur to the surface.