Download Ion Naming Patterns: Cations: positively charged ions Monoatomic

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