notes #12. review to find the number of valence electrons in an atom of a representative element,...
TRANSCRIPT
IONIC COMPOUNDSNotes #12
Review To find the number of valence electrons in
an atom of a representative element, simply look at its group number.
Why do atoms form ions?
To fulfill octet rule.
To be stable and happy like a noble gas.
They gain and lose electrons to have a COMPLETE outer shell.
But where do these electrons come from?
OTHER ELEMENTS!
This creates something we call:
Ionic Compounds: Compounds that are formed by
elements transferring their electrons to each other.
Ionic Bonds: The electrostatic forces that hold ions
together in ionic compounds.
Ionic Compounds: Properties Are electrically neutral (no charge!)
Most ionic compounds are crystalline solids at room temperature.
Ionic Compounds: Properties Ionic compounds generally have high
melting points. Ionic compounds can conduct an
electric current when melted or dissolved in water.
How Ionic Compounds are made:
Naming. Easy Peasy.
Write the actual name of the cation. Then, write the name of the anion
with the end ending in –ide. Ex: Nitrogen Nitride; Oxygen Oxide;
etc
Cations always first, Anions always last
Practice
Cation always First.Anion Always Last.
Must be neutral… Criss-Cross Rule
Polyatomic Ions
Find these on your handout:
Ionic Compounds with polyatomic ions: Write the chemical formula and
name it:
Magnesium and nitrate
Lithium and sulfate
Potassium and cyanide
Transition Metals (Groups 1B to 8B) They always form CATIONS.
Therefore, they will have a positive charge.
The charges of the cations of many transition metal ions must be determined from the number of electrons lost.
Transition metals can form more than one ion. (Exceptions: Ag+, Cd+2, and Zn+2)
Symbols and Names of Common Transition Metal Ions
Symbol Stock Name Classical Name
Cu+ Copper (I) ion Cuprous ion
Cu+2 Copper (II) ion Cupric ion
Fe+2 Iron (II) ion Ferrous ion
Fe+3 Iron (III) ion Ferric ion
Co+2 Cobalt (II) ion Cobaltous ion
Co+3 Cobalt (III) ion Cobaltic ion
Practice
Cobalt (III) fluoride Copper (II) chloride
Fe2O3
CuF
Lab Activity
Cut and Paste Ionic Compounds!