Binary Covalent Compounds

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Binary Covalent Compounds

• Composed of two non-metals
• can be same or different

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Two naming systems

• Stock system
• learned for ionic compounds
• official
• Traditional
• what hear on news
• what see on ingredient lists

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Both Traditional Stock

• Least electronegative of two elements goes first
• See table S

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Stock System

• 1st element must have Roman Numeral so
• figure out oxidation number

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Stock System Oxidation Number

• molecular substances DONT contain ions
• concept of oxidation for e- bookkeeping
• pretend all shared e- go to atom with higher
  electronegativity value
• atom with higher electronegativity value (-)
  oxidation
• atom with lower electronegativity value ()
  oxidation

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7 Rules for Oxidation Numbers

• for free, uncombined element is 0

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for monatomic ion charge on ion
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Ca2 2 Cl-1 -1 Al3 3
Fluorine is always (-)1
CF4
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4.
Hydrogen is nearly always ()1, except when
bonded to metal, then (-)1
LiH CaH2 NaH

• Oxygen is nearly always (-)2 EXCEPT when

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6.

• sum oxidation numbers in neutral compound is 0

sum of oxidation numbers in polyatomic
ion charge of ion
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Naming Binary Covalent Compounds

• Stock System

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CO2

• CO2
• C goes first less electronegative than O

Each O is -2
CO2
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Try SO3
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Try N2O3
N2O3
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Try P2O5
P2O5
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Naming Binary Covalent Compounds

• Traditional Naming System

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Traditional Naming

• less electronegative element named 1st
• stem 2nd element plus -ide ending
• prefixes tell how many of each element
• Exception NEVER start a name with mono-

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Prefixes Traditional System
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Traditional Naming
nitrogen monoxide