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4-1 Names and Symbols
most elements named for a property a symbol may be used in place of the name of the element it represents one atom of the element the first letter of a symbol is always capitalized symbols consist of 1 or 2 letters (a few odd 3 letter) 4-2 Chemical Formulas chemical formulas indicate the relative number of atoms of each element present in a compound a subscript in a formula represents the relative number of atoms of an element in the compound 4-3 Oxidation Numbers an ion is a charged atom or group of atoms that has lost or gained electrons. polyatomic ions consist of 2 or more atoms the charge on a single atom is called oxidation number also known as valence a monatomic ion consists of one atom or element TABLE 4-3 AND 4-4 PG 65 ionic compounds are composed of charged particles-net charge of compound is ZERO! weak bond molecular compounds are composed of neutral particles formed by the sharing of electrons in outer shells strong bond 4-4 Naming Compounds binary compounds contain 2 elements. Call the first one by its name and end the second one in "ide" (some non binary compounds end in ide ex. hydroxide, peroxide, carbide) prefix 2=di 3=tri 4=tetra 5=penta 6=hexa 7=hepta 8=octa MEMORIZE TABLE 4-3 PG 65 some atoms have more than one oxidation number a compound having such an element is named by showing the oxidation number as roman numerals in parenthesis after the element In naming polyatomic(old name radical) ions the name of the ion is not changed MEMORIZE TABLE 4-4 PAGE 65 negative polyatomic ions that contain oxygen(except OH- and peroxide) have the ending "ite" and "ate" acids have their own names MEMORIZE TABLE 4-9 PG 69 Organic naming based on number of atoms of carbon MEMORIZE TABLE 4-10 PAGE 70 and a suffix indicating how the carbon atoms are linked. 4-5 MOLECULAR AND EMPIRICAL FORMULAS A molecular formula describes the composition of a molecule An empirical formula indicates the simplest whole number ratio of atoms or ions in a compound 4-6 Coefficients a molecular formula is a whole number multiple of an empirical formula coefficients are used to represent the number of formula units |
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