Ionic Compounds
Chapter 8
Forming Chemical Bonds
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Chemical Bond: The force that holds two
atoms together.
Valence Electrons
Opposite forces attract
Octet Rule
Positive Ions
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Lose e- becomes cation.
Atoms can lose electrons to become more
stable.
Na+1 is more stable than Na.
Negative Ions
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Gain e- to become anions
Gain electrons to gain more stable e- config
Cl-1 is more stable than Cl
Formation of Ionic Bond
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Ionic Bond: electrostatic force that holds
oppositely charged particles together in an
ionic compound.
Occurs between metals and nonmetals.
Called ionic compounds.
Formation of Ionic Bond
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NaCl, 1 to 1 ratio of Na and Cl
Na+1 and Cl-1 combine
Oxidation numbers = 0
MgCl?
CaO
Properties of Ionic Compounds
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+ and – ions in regular pattern
Forms crystals EX: salt
Crystal lattice forms
Strong bonds between them
Have ↑ melting point and boiling point
If aqueous solution can conduct electricity
electrolyte.
Properties of Ionic Compounds
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Formation of ionic compounds is almost
always exothermic.
Lattice energy: amount of energy required to
separate ions of an ionic compound.
Smaller ions have more negative lattice
energy. EX: LiCl more negative NaCl
Larger charges have larger lattice energy.
EX: MgO more negative MgCl
Formulas for Ionic Compounds
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Formula Unit: Simples
ratio of ions in ionic
compound
Know your oxidation
states for monatomic
metals and nonmetals
Also know your
oxidation states for
polyatomic metals and
nonmetals
Group
1
Oxidation
number
1+
2
2+
15
3-
16
2-
17
3-
Oxidation Numbers
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Transition metals have multiple oxidation
numbers.
Oxidation number: # of e- transferred from an
element to form an ion.
Naming Ionic Compounds
1.
2.
3.
Cation always named first.
Cation name does not change. (Na1+,
sodium) Ex: NaCl = sodium chloride
Anion named by taking root and adding
–ide. (O2-, oxide) Ex: CaO = Calcium Oxide
Naming Ionic Compounds
4.
5.
Transition Metals with multiple oxidations
must include their oxidation state in the
name of the compound. [Fe2+, Iron (II)]
EX: FeO = Iron (II) oxide
EX: Fe2O3 = Iron (III) oxide
If an atom contains a polyatomic ion simply
name that ion. Know oxidation states of
polyatomic ions.
EX: NaOH = Sodium Hydroxide
EX: AgNO3 = Silver Nitrite
Naming Ionic Compounds
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Older method of naming transition metals
Root word followed by –ous, for lower
oxidation, or –ic, higher oxidation
EX: Cuprous ion = Copper (I)
EX: Cupric ion = Copper (II)
EX: Ferrous ion = Iron (II)
EX: Ferric ion = Iron (III)
Naming Ionic Compounds
Determine the cation
and anion of the given
formula
Does the cation have only one
oxidation number
Yes
Write name of cation and
then write name of anion
No
Write the name of the cation followed
by Roman numeral to represent the charge
Next write the anion.
Metallic Bonds and Properties of Metals
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Metals do not bond
ironically
Form electron sea
Electrons are not held
by 1 atom
Delocalized e-, free to
move
Metallic bond: attraction
of metallic cation for
delocalized e-.
Metallic Properties
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Very different melting points. Hg -38 C, W
3422 C.
Ductile and malleable.
Delocalized e- cause metals to be good
conductors.
Mobile e- interact with light releasing photons
causing luster.
Metal Alloys
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Alloy: mixture of elements that have metallic
properties. EX: steel, Brass
Substantial Alloy: atoms of original metallic
solid replaced by other metal atoms of similar
size
Interstitial Alloy: small holes in a metallic
crystal are filled with smaller atoms