Apply IUPAC nomenclature to name and write formulae for ionic, covalent and simple organic compounds

What this dot point is asking

VCAA wants you to name and write formulae for ionic, covalent and simple organic compounds following IUPAC conventions.

Ionic compounds

Cation first, anion second. Sodium chloride: Na$^+$ Cl$^-$ $\to$ NaCl.

Balance charges. Total positive charge equals total negative charge.

Variable-valency metals. Use Roman numerals to specify oxidation state. Iron(II) = Fe$^{2+}$; iron(III) = Fe$^{3+}$.

Polyatomic ions. Common ones to know:

• Nitrate NO$_3^-$, sulfate SO$_4^{2-}$, phosphate PO$_4^{3-}$, carbonate CO$_3^{2-}$, hydroxide OH$^-$, ammonium NH$_4^+$, acetate CH$_3$COO$^-$.

Covalent compounds (binary, non-metal-non-metal)

Prefixes specify the number of each atom. Mono-, di-, tri-, tetra-, penta-, hexa-, hepta-, octa-, nona-, deca-.

First element keeps its name; second gets "-ide" suffix.

Examples: CO carbon monoxide, CO$_2$ carbon dioxide, N$_2$O dinitrogen monoxide, N$_2$O$_5$ dinitrogen pentoxide, SF$_6$ sulfur hexafluoride.

Drop "mono-" on the first element (CO is carbon monoxide, not "monocarbon monoxide").

Simple organic compounds

Root names based on carbon chain length: meth- (1), eth- (2), prop- (3), but- (4), pent- (5), hex- (6).

Suffixes:

• -ane: alkane (single bonds, e.g. propane CH$_3$CH$_2$CH$_3$).
• -ene: alkene (one double bond).
• -yne: alkyne (one triple bond).
• -ol: alcohol (e.g. ethanol).
• -oic acid: carboxylic acid (e.g. ethanoic acid).
• -al: aldehyde.
• -one: ketone.
• -amine: amine.

Acids

Common Australian school acids:

• HCl hydrochloric acid.
• H$_2$SO$_4$ sulfuric acid.
• HNO$_3$ nitric acid.
• CH$_3$COOH ethanoic acid (acetic acid).
• H$_3$PO$_4$ phosphoric acid.

Worked example

Name FeCl$_3$.

Iron with chloride. Chloride is $-1$; for neutral compound, iron is $+3$. So Fe$^{3+}$: iron(III) chloride.

Common traps

Forgetting charge balance in ionic. Aluminium sulfate is Al$_2$(SO$_4$)$_3$, not AlSO$_4$.

Brackets for polyatomic ions when needed. When more than one polyatomic ion is needed, use brackets: Al$_2$(SO$_4$)$_3$, Mg(NO$_3$)$_2$.

Using "mono" on first element of covalent name. CO is carbon monoxide, not monocarbon monoxide.

Variable-valency metal without Roman numerals. Iron oxide is ambiguous (FeO or Fe$_2$O$_3$); specify iron(II) or iron(III).

In one sentence

IUPAC nomenclature names ionic compounds with cation first, anion second, and charges balanced (using Roman numerals for variable-valency metals); covalent compounds use numerical prefixes (di-, tri-, tetra-...) and the "-ide" suffix; simple organic compounds use root names (meth-, eth-, prop-) plus suffixes (-ane, -ene, -ol, -oic acid).