Inorganic and Organic Nomenclature

Naming and Writing Formulas for Inorganic Molecular and Ionic Compounds

Inorganic Molecular Compounds

• Bonds between two nonmetals.
• Name the first element as is.
• Name the second element and change the ending to "-ide".
• Use prefixes to determine the number of atoms of the second element (e.g., di-, tri-, tetra-).

Ionic Compounds

• Bonds between a nonmetal and a metal.

Simple Ionic Compounds

• Cation (positive ion) is given first; keep the name as is (no need to add anything).
• Anion (negative ion) is given second; change the ending to "-ide".
  • Example: $MgF_2$ (Magnesium fluoride), $NaCl$ (Sodium chloride).
• Moving backwards: Determine the charges and balance them to write the formula.
  • Example: Calcium nitride ( $Ca<em>3N</em>2$ ), Aluminum sulfide ( $Al<em>2S</em>3$ ).

Transition Metals

• Name the cation (metal).
• Give the Roman numeral indicating the charge of the cation.
• Name the anion with the ending changed to "-ide".
• Example: $FeCl_2$ (Iron (II) chloride).
• Moving backwards: Determine the charge from the Roman numeral and balance with the anion.
  • Example: Manganese (VII) sulfide ( $Mn<em>2S</em>7$ ).
• Net charge is 0 for all ionic compounds.

Polyatomic Ions

• Same rules apply as before.
• If paired with a transition metal, write the Roman numeral of charge, which will be determined by the polyatomic ion's charge.
  • Only need a Roman numeral because transition metals have multiple charges.
• No need for Roman numerals for metals with a fixed charge.
• Polyatomic ions end in "-ite" or "-ate" (and exceptions).
• Use parentheses if more than one polyatomic ion is needed.
• Don't change the ending of the polyatomic ion; leave as is.
  • Example: $FeCO<em>3$ (Iron (II) carbonate), $NaBrO</em>3$ (Sodium bromate).
• Moving backwards: Figure out the charge (either from the Roman numeral or fixed charge), then balance.

Organic Chemistry: Alkanes, Alkenes, and Alkynes

General Information

• An organic compound has at least one carbon atom bonded to a hydrogen atom.
• Carbon has 4 bonds.
• Lewis structures: Each corner is a carbon, and each edge represents a bond.
• Carbon skeleton: Only shows carbon atoms, no hydrogen atoms.
• Condensed formula: Shows the arrangement of atoms.
  • Example: $CH<em>3CH</em>2CH_3$.

Naming Alkanes

• Find the longest carbon chain.
• Prefix indicates the number of carbons in the chain; the suffix is "-ane".
• If there is a branch, number the chain to indicate the location of the branch.
• Use a prefix to determine how long the branch is; the suffix is "-yl" for the branch.
• If multiple of the same branch, use prefixes like di-, tri-, tetra- in addition to the location.
• Name branches in alphabetical order.
  • Example: $CH<em>3CH(CH</em>3)CH<em>2CH</em>2CH_3$ is 3-Methylpentane
• Isomers: molecules that have the same condensed molecular formula but different structures, and thus different names.

Alkenes and Alkynes

• Alkenes contain at least one double bond; the suffix is "-ene".
• Alkynes contain at least one triple bond; the suffix is "-yne".
  • Example: Butene ($C<em>4H</em>8$) ; Butyne ($C<em>4H</em>6$)
• Use a number to indicate where the double or triple bond is located on the chain.
• cis-isomers have substituents on the same side of the double bond.
• trans-isomers have substituents on opposite sides of the double bond.
• cis and trans are only applicable to alkenes.
• When numbering, number so the double or triple bond has the lowest number on the parent chain.
• Cis or trans precedes the name if an isomer exists.