Naming Compounds

Naming Chemical Compounds

• Naming is important as it provides clues to the compound's identity.
• Rules for naming covalent and ionic compounds are similar with some differences.
• Must understand how to name chemical species and identify the correct species from its name.

Naming Ionic Compounds

• Ionic compounds are named using the cation (metal) first and the anion (non-metal) second.

Cations

• Cations retain their elemental name for all metals, including transition metals, without any suffix or prefix.
• Example: $CaCl_2 = Calcium Chloride$
• Transition metals include Roman numerals indicating their oxidation state (number of valence electrons).
• Most metal elements (except transition metals) have a predetermined number of valence electrons, so they don't need Roman numerals.

Anions

• Anions retain the root of their elemental name but gain the suffix '-ide'.
• The '-ide' suffix commonly represents negatively charged atoms.
• Example: $CaCl_2 = Calcium Chloride$

Naming Covalent Molecules

• Covalent compounds are named similarly to ionic compounds, but require extra information because all bonded atoms are non-metals.
• The most electronegative atom receives the '-ide' suffix and is named second.
• The least electronegative atom does not receive a suffix and is named first.
• Example: $CO_2 = Carbon Dioxide$
• Prefixes are assigned to all atoms based on the number of atoms present in the molecule.
• The first atom (least electronegative) does not receive a prefix if only one atom is present; otherwise, it does.
• Prefixes indicate the number of specific atoms bonded.
• Examples:
  • $H_2O = Water \;or\; Dihydrogen \;monoxide$
  • $CO_2 = Carbon \;Dioxide$
  • $N<em>2O</em>5 = Dinitrogen \;pentaoxide\;(pentoxide)$

Naming Organic Covalent Molecules

• Organic covalent compounds are molecules containing carbon and hydrogen.
• Organic compounds typically include longer carbon chains, so they have specific naming rules.
• Three types of organic groups:
  1. Alkanes
  2. Alkenes
  3. Alcohols
• Must be able to identify and name these compounds.

Alkanes

• Covalently bonded compounds with a series of carbon and hydrogen bonds (-CH).
• General formula: $C<em>nH</em>{2n+2}$
• Naming depends on the number of carbons and the priority functional group.
• A functional group is a distinguishable group of atoms with identifiable chemical or physical characteristics.
• Focus on simple names and groups.
• The base of organic compound names depends on the number of carbons.
• Suffix for alkanes is '-ane'.
• Examples:
  • 1 Carbon: Meth- (Methane)
  • 2 Carbons: Eth- (Ethane)
  • 3 Carbons: Prop- (Propane)
  • 4 Carbons: But- (Butane)
  • 5 Carbons: Pent- (Pentane)
  • 6 Carbons: Hex- (Hexane)
  • 7 Carbons: Hept- (Heptane)

Alkenes

• A series of carbon-hydrogen bonds that include a carbon-carbon double bond.
• General formula: $C<em>nH</em>{2n}$
• Requires carbon-carbon double bonds (C=C), so the lowest carbon count/base is 2 (eth-).
• Suffix for alkenes is '-ene'.
• Uses the same base as alkanes.
• Examples:
  • 2 Carbons: Ethene
  • 3 Carbons: Propene
  • 4 Carbons: Butene
  • 5 Carbons: Pentene
  • 6 Carbons: Hexene
  • 7 Carbons: Heptene

Alcohols

• Similar to alkanes, but include one or more hydroxy groups (-OH).
• General formula: $C<em>nH</em>{2n+2}O$
• Alcohols have unique interactions and a wide range of applications.
• Suffix for alcohols is '-anol'.
• Uses the same base as alkanes.
• Examples:
  • 1 Carbon: Methanol
  • 2 Carbons: Ethanol
  • 3 Carbons: Propanol
  • 4 Carbons: Butanol
  • 5 Carbons: Pentanol
  • 6 Carbons: Hexanol
  • 7 Carbons: Heptanol

End of Class Questions

• Name the following ionic compounds (KBr, NaCl, $CaI_2$, FeO, CuP)
• Name the following covalent compounds ($H<em>2S$, $SO</em>2$, $NO<em>3$, $N</em>4O_4$)
• Give the molecular formula according to the following names
  • Trinitrogen hexaoxide, Carbon monoxide, Carbon tetrafluoride
• Name the following covalent molecules ($C<em>5H</em>{12}$, $C<em>4H</em>8$)
• Using the following condensed formula ($CH<em>3CH</em>2CH_2OH$), give the molecular formula and name of the molecule.