Transcript Ionic Compounds - SCH3U-CCVI

Ionic Compounds
Outline
Ionic Compounds
Ionic Compounds
Ionic compounds are made up of positive and
negative ions.
These ions result from the transfer of
electrons from a metal to a non-metal.
The positive and negative ions are attracted
to each other because they have opposite
charges.
Ionic Compounds
Calcium transfers
two electrons, one to
each fluorine atom
All three ions are stable
(max. # of electrons in
valence shell.)
Chemical Formulas
Are a combination of element symbols
and subscripts that represents a
particular compound.
Element symbol
Eg.
C2H4O6
Subscripts (indicate the
number of ions of
each type.)
Naming Ionic Compounds
The name of the metal is first.
The name of the non-metal is second.
But – the ending of the non-metal changes
to “ide”
Eg. The compound formed by calcium and
iodine = calcium iodide
How to Write the Chemical
Formula for Ionic Compounds
Eg.
Ionic Compound formed by calcium
and fluorine
Step 1.
Write the symbols, with the metal
first.
Ca
F
How to Write the Chemical
Formula for Ionic Compounds
Step 2.
Write the ionic charge above each
symbol to indicate the stable ion
that each element forms.
2+
Ca
1-
F
How to Write the Chemical
Formula for Ionic Compounds
Step 3. Crisscross the ionic charges to
produce subscripts.
2+
Ca
1-
F
How to Write the Chemical
Formula for Ionic Compounds
Step 4.
Write the formula using subscripts
to indicate the number of ions of
each type. Reduce the number of
subscripts if possible.
Ca1F2
Reduced:
CaF2
Name of Compound: Calcium fluoride
How to Write the Chemical
Formula for Ionic Compounds
Eg. Ionic compound formed by aluminum and
sulfur
Steps 1-3:
Step 4:
3+
Al
2S
Al2S3
Name of compound: Aluminum Sulfide
How to Write the Chemical
Formula for Ionic Compounds
Eg. Ionic compound formed by magnesium and oxygen.
Steps 1-3:
2+
Mg
Step 4:
Mg2O2
2O
Reduce: MgO
Name of compound: Magnesium Oxide
Multivalent Metal Elements
Some metals form more than one
kind of ion.
A Roman numeral is added to the
metal name to indicate its ionic
charge.
Multiple Ionic Charges
Name
Symbol
Copper
Cu
Iron
Fe
Lead
Pb
Tin
Sn
Ionic
Charge
1+
2+
2+
3+
2+
4+
2+
4+
Roman
Numeral
I
II
II
III
II
IV
II
IV
Multivalent Metal Elements
Going from formula to name:
1. Metal name unchanged
2. Find the charge on the metal using reverse
crossover
3. Add the metal’s change using roman
numbers (I, II, III, IV, etc..)
4. Non metal name with ‘ide’ ending
*Be sure to watch for compounds that have
already been reduced*
eg.
– CuCl  copper (I) chloride
– CuCl2  copper (II) chloride
Multivalent Metal Elements
Going from name to formula:
1.
2.
Write each element’s symbol and charges. (For
metal use number in roman numerals as the charge).
Crossover and simplify when needed.
eg.
–
copper (I) chloride  CuCl
–
copper (II) chloride  CuCl2
Classical (Alchemist) Method:
Suffix added to ‘root’ name (must
memorize)
Suffix: higher charge (‘ic’)
lower charge (‘ous’)
Eg. Cupric oxide (copper with charge of +2)
plumbous chloride (lead with charge of
+2)