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Ch. 5.2 Notes. Ionic Bonding and Salts. Ionic Bonds. Cations (+) lose 1 or more e- Anions (-) gain 1 or more e- Receive/give e- from/to one another Resulting + and – charges are attracted, form an ionic bond Bond creates a compound. Example…. NaCl – sodium chloride (table salt) - PowerPoint PPT Presentation
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Ch. 5.2 NotesIonic Bonding and Salts
Ionic Bonds Cations (+) lose 1 or more e- Anions (-) gain 1 or more e-
Receive/give e- from/to one another
Resulting + and – charges are attracted, form an ionic bond
Bond creates a compound
Example… NaCl – sodium chloride (table salt)
Ionic compound Na Na+ + e- Cl + e- Cl-
The e- lost by Na is gained by Cl Positive Na+ is attracted to negative Cl-
Energy changes Transferring electrons/forming compounds involves energy
changes Na + energy Na+ + e-
What is this energy called? Cl + e- Cl- + energy Overall formation of ionic compound (also called a salt)
releases energy
Energy changes Salt formation involves
endo- and exothermic steps
Overall reaction is exothermic Amount of energy
released when ionic bonds formed is called lattice energy
Ionic compounds Ratio of anions to cations always reflects a neutral charge
For every 1 Na+, there’s 1 Cl-
For every 1 Mg2+, there’s 1 O2-
For every 1 Ca2+, there are 2 Cl-
Ionic compounds Don’t consist of
molecules Form crystal lattice
Ex. NaCl – multiple ions bonded together, but still maintain the ration necessary for a neutral compound
Variations in ionic crystal lattices
Properties of Ionic Compounds Strong bonds High melting and boiling points Rarely gaseous at room temp. Hard Brittle – break along a cleavage
plane
Properties of Ionic Compounds Conduct electric current
(Typically) only when the ions can move around freely, aren’t locked into lattice
This happens if ionic compound is in liquid state or dissolved