Ionic Compounds
Ion formation
• Octet rule- atoms want a full valence shell
▫ _____ valence electrons for most atoms
▫ ____ and atoms that become isoelectronic with __ are
satisfied with ____ valence electrons
▫ H can be satisfied with ___ or ___
• _____________
▫ Low electronegativities and ionization energies
▫ Electrons are __________ until octet rule is satisfied
(more complicated in the transition metals)
• ______________
▫ High electronegativities and ionization energies
▫ Electrons are ________ until octet rule is satisfied
Valence electrons
Ions
• An atom with a _____________
▫ Imbalance of _________ and _________
▫ _____ or ______ electrons
• Two Types
▫ Cation- __ charge because electrons are __
 Cation with a common charge
 Multivalent cation
 Polyatomic cation
▫ Anion- _ charge because electrons are ____
 Anion with a common charge
 Polyatomic anion
Cations with a
Common Charge
• Atoms that predictably form a cation with a
certain charge
• Group 1 elements- form cations with __
charge
• Group 2 elements- form cations with ___
charge
• Al- forms cations with a ___ charge
• Some of the other metals will also only form
one common ion
Multivalent Cations
• Atoms that form multiple types of cations
• All other metals not on the common cation list
Polyatomic Cations
• Cation made up of multiple atoms bonded
together
• You only memorized one
+
NH4+
Naming Cations
• Cations with a common charge
▫ “Element name” ion
 For example
 Na+ is _____________
 Ca+2 is _____________
• Multivalent cations
▫ “Element name” (Roman numeral for charge) ion
 For example
 Fe+2 is _____________
 Fe+3 is _____________
• Polyatomic cations
▫ “Polyatomic name” ion
 NH4+ is _______________
Anions with a
Common Charge
• Atoms that predictably form a anion with a
certain charge
• Group 17 non-metals- form anions with __ charge
• Group 16 non-metals- form anions with __
charge
• Group 15 non-metals- forms anions with a ___
charge
• Sometime Group 14 non-metals form anions with
a ____ charge
2-
Polyatomic Anions
CO32-
• Anion made up of multiple atoms bonded
together
• You memorized 10, but by learning a set of
rules you know more than 10.
• For polyatomics with oxygen ending with –
ate
▫ Add one more oxygen, name is _________
▫ Take away one oxygen, name is ________
▫ Take away two oxygens, name is ________
Polyatomic Anions (cont)
• For example:
▫ You memorized ClO3- is chlorate
 This ion has one chlorine and three oxygen atoms with a
negative one charge
▫ ClO4- is _____________
 This ion has one chlorine and four oxygen atoms (one
more than the –ate ion) with a negative one charge
▫ ClO2- is ____________
 This ion has one chlorine and two oxygen atoms (one
less than the –ate ion) with a negative one charge
▫ ClO- is _____________
 This ion has one chlorine and one oxygen atom (two less
than the –ate ion) with a negative one charge
Naming Anions
• Anions with a common charge
▫ “Element name with ending changed to -ide” ion
 For example
 Cl- is ____________
 O-2 is ____________
• Polyatomic anions
▫ “Polyatomic name” ion
 For example
 CO3-2 is ___________
 NO3- is ___________
 NO2- is ___________
Ionic bonding
• Ions of opposite charges are
attracted to each other
• This attraction is a chemical
bond
F
Na
Electron is transferred
Na
F
Charges
+1
Na
-1
F
Atoms are attracted to each other
+1
Na
F
-1
And each have 8 valence electrons
Bonds
• Chemical bonds are _______________
• They act between atoms within a molecule
Why does bonding occur?
• Bonding occurs to maximize stability of
the atoms involved.
• More stable = LOWER potential energy
Ionic Compounds
• Will often form a crystal structure
• Can be identified by name or
formula
▫ If given one, you can find the
other
▫ Formulas give the smallest whole
number ratio between the ions
Naming Ionic Compounds
• Determine the name of the cation and anion
involved in the ionic bond
• Name both (cation before anion) leaving off the
“ion”
▫ For example
 An ionic compound between a magnesium ion and a
fluoride ion would be ________________
 An ionic compound between a copper (I) ion and a
phosphate ion would be _________________
Formulas
• Elements in the compound are listed with
the number of atoms of each type listed as
subscripts
▫ For example, NaCl
 Has a 1:1 ratio of sodium ions to chloride ions
▫ CaI2
 Has a 1:2 ratio of calcium ions to iodide ions
Formulas (cont.)
• Formulas with polyatomic ions can have
parenthesis with a subscript on the outside
• The subscript on the outside denotes how many
polyatomic ions are there
▫ For example, Al(NO3)3
 Has a 1:3 ratio of aluminum
ions to nitrate ions
Switching Between Names and
Formulas
• Name to Formula
▫ Identify the symbol and charge of the anion and the
cation
▫ Determine how many of cations and anions are
needed to balance the charges to neutral
▫ Write the formula (cation first) with subscripts
denoting how many are needed of each ion
 Remember to put polyatomic ions in parenthesis if
adding a subscript to them
Switching Between Names and
Formulas
Name to Formula example
▫ What is the formula for calcium bromide?
Switching Between Names and
Formulas
Name to Formula example
▫ What is the formula for iron (II) chloride?
Switching Between Names and
Formulas
Name to Formula example
▫ What is the formula for potassium hydroxide?
Switching Between Names and
Formulas
• Name to Formula example
▫ What is the formula for gold (II) phosphate?
Switching Between Names and
Formulas
• Name to Formula example
▫ What is the formula for ammonium bromide?
Switching Between Names and
Formulas
• Formula to name
▫ Identify the name of the cation and anion in the
formula
 Remember multivalent cations need a Roman numeral
as part of their name. You will have to determine the
charge from the formula clues.
▫ Name the compound
Switching Between Names and
Formulas
• Formula to name examples
▫ LiBr
▫ NiO