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Ion Naming Patterns: 1. Cations: positively charged ions 1. Monoatomic cations: name stays the same as the neutral atom Example: Na: Sodium Na+: Sodium Al: Aluminum Al3+: Aluminum 2. Transition metals have more than one possible charge so you must use Roman Numerals to say what charge the metal ion has Example: Iron (II): Fe2+ Iron (III): Fe3+ + Copper(I): Cu Copper(II): Cu2+ 3. Polyatomic cation: 1. Ammonium: NH4+, 2. This is an unusual cation because most cations are made of metals, but this one is made of non-metals. 3. The bonds between the N and H are covalently bonded. 4. Treat polyatomic ions as one unit. Sometimes students want to leave the 4 off or change the charge, but you can't do that. 5. The whole ion (which consists of 5 atoms) has a +1 charge. If you add up all the protons from the 4 H atoms and the N atom and compare that to the total number of electrons for the 4 H atoms and N atom, you will have one more proton than electron. 2. Anions: negatively charged ions 1. Monoatomic anions get the “-ide” ending 1. Monoatomic means single atom; these are the ions you predict from periodic table based on number of valence electrons and how close they are to a full outer shell. Examples: F-1: Fluoride Cl-1: Bromide O2-: Oxide N-3: Nitride Just a note to remind you that it doesn't matter what order you write the symbols for the charge... -3 is the same as 3-, -2 is the same as 2-, etc. 2. Polyatomic anions have a variety of endings and generally just have to be memorized. 1. “-ate” means bonded to oxygen, either 3 or 4 oxygen atoms Example: NO3-1: Nitrate SO42-: sulfate 2. “-ite” means bonded to oxygen, always one less oxygen than the “-ate” form Example: NO2-1: Nitrite SO32-: sulfite 3. Remember: 1. Polyatomic ions are treated as one unit. 2. The charge is shared amongst all the atoms 3. There is more than one atom in a polyatomic ion 4. The atoms are covalently bonded to each other How do ions bond? Ions bond so that the compound has no charge Positive charges are balanced by negative charges o Ex: NaCl, +1 charge of Na+ balances the -1 charge of Clo Ex: FeCl2, +2 carge of Fe+2 balances the two -1 charges of the Cl- ions. How do we write chemical formulas of ionic compounds? Write cation first, anion second Make sure charges cancel out When balancing charge using polyatomic ions, act as if polyatomic ion is one atom. o Ex: NaHCO3, +1 charge of Na+ balances -1 charge of HCO3o Ex: NH4OH, +1 charge of NH4+ balances -1 charge of OH When you have to use more than one polyatomic ion, use parentheses Ex: Fe(OH)3 o Ex: Al2(SO4)3 o When dealing with two ions that have unequal charges, make the charge of one be the subscript of the other and vice versa o Ex: Al2O3. Charge of O2- is 2, so make 2 subscript on Al Charge of Al3+ is 3, so make 3 subscript on O How do we write the names of compounds? Write the cation first than the anion For transition metals which have more than one oxidation state, use number in parentheses to describe charge. o FeCl2 = Iron (II) Chloride o FeCl3 = Iron (III) Chloride Old names: If you use the old names, you don’t need to use numbers in parentheses Ferrous = Iron (II) Ferric = Iron (III) Cuprous = Copper (I) Cupric = Copper (II) Stannous = Tin (II) Stannic = Tin (IV) Plumbous = Pb (II) Plumbic = Pb (IV) Examples o FeCl2 = Ferrous Chloride o CuCl2 = Cupric Chloride