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Flashcards in Ch 7 Section 1 Deck (72):
1

common names usually give no information about

chemical composition

2

to describe atomic makeup of compounds chemists use

systematic methods for naming compounds and for writing chemical formulas

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for a molecular compound, the chemical formula reveals the number of atoms of each element contained in a

single molecule of the compound

4

an ionic compound consists of a lattice of

positive and negative ions held together by mutual attraction

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the chemical formula for an ionic compound represents one formula unit--the

simplest ratio of the compound's positive ions and its negative ions

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parentheses surround the polyatomic anion to

identify it as a unit

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when there is no subscript written next to an atom's symbol, the value of the subscript is

understood to be 1

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monatomic ions are ions formed from a

single atom

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not all main-group elements readily

form ions
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atoms of carbon and silicon form

covalent bonds in which they share electrons with other atoms
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other elements tend to form ions that do not have

noble-gas configurations.
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elements from the d-block form

2+, 3+, 1+, or 4+ cations
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Many d-block elements form two

ions of different charges
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monatomic cations are identified simply by

the elements name
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in naming monatomic anions the ending of the element's name is

dropped and replaced with -ide
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numerals used in the naming of ions are part of the

stock system of naming chemical ions and elements
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binary compounds are compounds composed of

two elements
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in a binary ionic compound the total numbers of positive charges and

negative charges must be equal
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the formula for a binary compound can be written given the

identities of the compound's ions
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in binary ionic compounds the charges of the compounds are not

included in the formula
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crossing over is a method of balancing the

charges between ions in an ionic compound
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Step 1 for cross over method

write the symbols for ions side by side, with cation first
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step 2 for cross over: cross over the

charges by using the absolute value of each ion's charge as the subscript for the other ion
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step 3 for cross over: check the subscripts and divide them by their

largest common factor to give the smallest possible whole-number ratio of ions. then write the formula
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nomenclature

naming system
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the nomenclature of binary ionic compounds involves combining the names of the

compound's positive and negative ions
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for most simple ionic compounds, the ratio of the ions is not indicated in the compound's name because it is

understood based on the relative charges of the compound's ions
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some elements form two or more

cations with different charges

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to distinguish ions formed by elements that form 2 or more cations with different charges, scientists use the

stock system of nomenclature
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stock system uses a roman

numeral to indicate an ions charge
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numeral is enclosed in parentheses and is

placed immediately after the metal name
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names of metals that commonly form only one cation do not

include a Roman numeral
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there is no element that commonly forms more than

one monatomic anion

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oxyanions are polyatomic ions that

contain oxygen
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the name given a compound containing an oxyanion depends on the

number of oxygen atoms in the oxyanion
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(oxyanions) the name of the ion with the greater number of oxygen atoms ends in

-ate
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(oxyanions) the name of ion with smaller number of oxygen atoms ends in

-ite

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sometimes an element can form more than two types of

oxyanions
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an anion that has one fewer oxygen atom than the -ite atom has is given the prefix

hypo-

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an anion that has one more oxygen atom that the -ate anion has is given the prefix

per-

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compounds containing polyatomic ions are named in the same manner as

binary ionic compounds
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unlike ionic compounds molecular compounds are composed of individual

covalently bonded units (molecules)
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chemists use two nomenclature systems to name

binary molecules
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he newer system is the stock system for naming molecular compounds, which requires

an understanding of oxidation numbers
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the old system of naming molecular compounds is based on the use of

prefixes

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mono-

1

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di

2

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tri

3

49

tetra

4

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penta

5

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hexa

6

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hepta

7

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octa

8

54

nona

9

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deca

10

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(rules for prefix system) element that has the smaller group number is usually

given first

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(rules for prefix system) if both elements are in the same group, the element whose period number is greater is

given first

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(rules for prefix system) the element is given a prefix only if it

contributes more than one atom to a molecule of the compoudn
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(rules for prefix system) the second element is named by combing (a) a prefix indicating the

number of atoms contributed the element, the root of element's name, and ending-ide
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(rules for prefix system) with few exceptions, the ending ide indicates that a compound contains only

2 elements

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(rules for prefix system) the o or a at the end of a prefix is usually dropped when the word following begins with

another vowel

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in covalent network compounds there are no distinct

units

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the subscripts in a formula for covalent-network compound indicate the

smallest whole-number ratio of the atoms in the compound
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an acid is a distinct type of

molecular compound

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most acids used in the lab can be classified as either

binary acids or oxyacids
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binary acids are acids that consist of

two elements, usually hydrogen and one of the halogens
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oxyacids are acids that contain

hydrogen, oxygen, and a third element (usually nonmetal)
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the term acid typically refers to a solution in water of one of these

special compounds rather than to the compound itself
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many polyatomic ions are produced by the loss of hydrogen

ions from oxyacids

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a salt is an ionic compound composed of a

cation and the anion from an acid
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some salts contain anions in which

one or more hydrogen atoms from the acid are retained
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such anions are named by adding the word

hydrogen or prefix bi- to anion name