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Naming Ions and Writing Formulas for Ionic Compounds. Monoatomic ions. Defined as a single atom with a charge Cation = + charge from losing an e- Anion = - charge from gaining an e- Cations are named by taking the name of the element and adding “ion”. For example: Na+ sodium ion
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Monoatomic ions • Defined as a single atom with a charge • Cation = + charge from losing an e- • Anion = - charge from gaining an e- • Cations are named by taking the name of the element and adding “ion”. For example: Na+ sodium ion Mg2+ magnesium ion • Anions are named by dropping the end of the element name and adding the ending –ide. (Generally you keep the 1st syllable and drop the rest. We will go over the exceptions.) For example: O2- oxide Cl- chloride
-1 Charge Acetate CH3COO- or C2H3O2- Nitrite NO2- Nitrate NO3- Cyanide CN- Hydroxide OH- Hypochlorite ClO- Chlorite ClO2- Chlorate ClO3- Perchlorate ClO4- -2 Charge Sulfite SO32- Sulfate SO42- Carbonate CO32- -3 Charge Phosphate PO43- +1 Charge Ammonium NH4+ Polyatomic ionsIons composed of more than one atom.(You will need to memorize most of these.)
NAMING/WRITING BINARY IONIC COMPOUNDS • Binary Ionic Compound = A compound made of two kinds of elements. • Examples: NaCl, MgBr2, FeI3
Writing the formulas Cation (+) first Anion (-) last “criss-cross” method Naming the formulas Cation (+) first Anion (-) last Examples: NaCl sodium chloride MgBr2 magnesium bromide FeI3 iron iodide
Writing the formulas Cation (+) first Anion (-) last “criss-cross” method Naming the formulas Cation (+) first Anion (-) last Examples: NH4Cl ammonium chloride Ca(OH)2 calcium hydroxide Na2SO4 sodium sulfate NAMING/WRITING COMPOUNDS WITH POLYATOMIC IONS
Stock Systemusing Roman numerals in nomenclature • Used for transition metals with more than one possible charge (there are others) FOR EXAMPLE: FeCl2 and FeCl3 are both iron chloride. To differentiate, use the stock system: • FeCl2 = iron (II) chloride • FeCl3 = iron (III) chloride
Hinge Questions: Write the names for these formulas. • CaI2 • NiO • Al2S3