Common Polyatomic Ions

Flashcards covering common polyatomic ions ending in '-ate' and the mnemonic rule used to memorize their chemical formulas and charges.

Polyatomic Ion Mnemonic Sentence

Nick the Crafty Camel ate an Inch Clam and drank a Brew for Supper in Phoenix

Nitrate

$NO_3^-$ (represented by 'Nick' in the mnemonic: starts with N, 3 consonants = 3 O's, 1 vowel = -1 charge)

Chromate

$CrO_4^{2-}$ (represented by 'Crafty' in the mnemonic: starts with Cr, 4 consonants = 4 O's, 2 vowels = -2 charge)

Carbonate

$CO_3^{2-}$ (represented by 'Camel' in the mnemonic)

Iodate

$IO_3^-$ (represented by 'Inch' in the mnemonic)

Chlorate

$ClO_3^-$ (represented by 'Clam' in the mnemonic)

Bromate

$BrO_3^-$ (represented by 'Brew' in the mnemonic)

Sulfate

$SO_4^{2-}$ (represented by 'Supper' in the mnemonic)

Phosphate

$PO_4^{3-}$ (represented by 'Phoenix' in the mnemonic)

Polyatomic Ion Mnemonic Sentence

Nick the Crafty Camel ate an Inch Clam and drank a Brew for Supper in Phoenix

Nitrate

$NO_3^-$ (represented by 'Nick' in the mnemonic: starts with N, 3 consonants = 3 O's, 1 vowel = -1 charge)

Chromate

$CrO_4^{2-}$ (represented by 'Crafty' in the mnemonic: starts with Cr, 4 consonants = 4 O's, 2 vowels = -2 charge)

Carbonate

$CO_3^{2-}$ (represented by 'Camel' in the mnemonic)

Iodate

$IO_3^-$ (represented by 'Inch' in the mnemonic)

Chlorate

$ClO_3^-$ (represented by 'Clam' in the mnemonic)

Bromate

$BrO_3^-$ (represented by 'Brew' in the mnemonic)

Sulfate

$SO_4^{2-}$ (represented by 'Supper' in the mnemonic)

Phosphate

$PO_4^{3-}$ (represented by 'Phoenix' in the mnemonic)

Ammonium

$$NH_4^+$$

Hydroxide

$$OH^-$$

Cyanide

$$CN^-$$

Acetate

$C<em>2H</em>3O<em>2^-$ (or $CH</em>3COO^-$)

Rule for '-ite' suffix

Remove 1 oxygen atom from the '-ate' ion while keeping the same charge (e.g., Nitrate $NO<em>3^-$ becomes Nitrite $NO</em>2^-$)

Nitrite

$$NO_2^-$$

Sulfite

$$SO_3^{2-}$$

Perchlorate

$ClO_4^-$ (one more oxygen than chlorate)

Chlorite

$ClO_2^-$ (one less oxygen than chlorate)

Hypochlorite

$ClO^-$ (two less oxygens than chlorate)

Rule for 'Hydrogen' prefix

Add $H^+$ to the front of the formula and add $+1$ to the charge (e.g., Carbonate $CO<em>3^{2-}$ becomes Hydrogen Carbonate $HCO</em>3^-$)

Hydrogen Carbonate

$$HCO_3^-$$

Hydrogen Phosphate

$$HPO_4^{2-}$$