211nomenclature_spr2011 - N om e n c l a t u r e Dr. G. L.R.

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1 Nom e n c latur e Dr. G. L.R. Weatherspoon-Chem 211 GMU When instructors talk about the properties of chemicals it is critical that you recognize the chemical that is being discussed. For example, if during the discussion of chemical reactions an instructor mentions that potassium chlorate is heated to produce potassium chloride and oxygen, it is critical that you are able to write the chemical reaction for this process. Thus you must learn chemical nomenclature as soon as possible. As further impetus, studies show a good correlation between learning nomenclature and final course grade. How do you learn chemical nomenclature? You practice and practice and practice. However, sitting alone in a room memorizing chemical nomenclature for hours and hours is probably not something most students would savor, and you are therefore urged to work on a few nomenclature problems from the text each day until you master chemical nomenclature. Please read over the following notes carefully before beginning the problems. I. IONIC COMPOUNDS A. Cations 1. Monatomic a) Monatomic cations are most commonly formed from metallic elements. They take the name of the element itself: Na + sodium ion Zn 2+ zinc ion b) If an element can form more than one positive ion, the positive charge of the ion is indicated by following the name of the metal with a Roman numeral in parenthesis: Fe 2+ iron(II) ion Cu + copper(I) ion Fe 3+ iron(III) ion Cu 2+ copper(II) ion Experience is needed to know which elements commonly exist in more than one charge state. An older method still widely used for distinguishing between two differently charged ions of a metal uses the endings -ous or -ic; these endings represent the lower and higher charged ions, respectively. They are used together with the Latin root to name the ion: Fe 2+ ferrous ion Cu + cuprous ion Fe 3+ ferric ion Cu 2+ cupric ion 2. Polyatomic a) The only common polyatomic cations are those give below: NH 4 + ammonium ion Hg 2 2+ mercury(I) or mercurous ion The name mercury(I) ion is given to Hg 2 2+ because it can be considered to consist of two Hg + ions. Mercury also occurs as the monatomic Hg 2+ ion, which is known as the mercury(II) or mercuric ion. B. Anions 1. Monatomic Negative ions are called anions. Monatomic anions are most commonly formed from atoms of the nonmetallic elements. They are named by dropping the ending of the name of the element and adding the ending -ide:
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2 H - hydride ion O 2- oxide ion N 3- nitride ion F - fluoride ion S 2- sulfide ion P 3- phosphide ion 2. Polyatomic a) Only a few common polyatomic ions end in -ide: OH - hydroxide ion CN - cyanide ion O 2 2- peroxide ion b) There are many polyatomic ions containing oxygen. Anions of this kind are referred to as oxyanions. A particular element, such as sulfur, may form more than one oxyanion. When this occurs, rules for indicating the relative numbers of oxygen atoms in the anion are used. When an element has two oxyanions, the name of the one that contains more oxygen ends in -ate; the name of the one with
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This note was uploaded on 03/03/2011 for the course CHEM 211 taught by Professor Papanastasiou during the Spring '07 term at George Mason.

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211nomenclature_spr2011 - N om e n c l a t u r e Dr. G. L.R.

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