Transcript 1. Ionic Compound NEW

Ionic Compounds
Learning Goals
• Describe the relationship between chemical
formulae, composition, and names of ionic
compounds
• Describe the properties of ionic compounds
Warm-Up
1. Why do we name objects, people, pets,
elements, etc.?
2. Do all names stay the same? Do your names
always stay the same?
Ionic Bonding
• Metals
– Electron donors
– Donate their valence
electrons to become
a positive ion (cation)
• Nonmetals
– Electron acceptors
– Accept valence electrons to become a
negative ion (anion)
Ionic Bonding
Ionic Bonding
The oppositely charged ions are
attracted to each other by a
force called an ionic bond
Properties of Ionic Compound
• Most ionic compounds:
• Have high melting points
• Are hard and brittle
• Are soluble in water
• Form electrolytes (conduct electricity)
when dissolved in water
Crystal Lattice Structure
• Ionic compounds form crystal
lattices
• This explains why they have
high melting points and are
hard but brittle
Na+
Cl-
Ionic Compounds in Water
When ionic
compounds dissolve,
they separate into
their ions
The free ions can now
move and conduct
electricity
Naming Ionic Compounds
• Many ionic compounds are made up of a
metal and a nonmetal
• The metal is named first, followed by the
nonmetal
• Change the nonmetal ending to “ide”
E.g. aluminum and oxygen = aluminum oxide
magnesium and chlorine = magnesium chloride
Do NOT capitalize
Common Anions
Name
H-
hydride
F-
fluoride
Cl-
chloride
Br-
bromide
I-
iodide
O2-
oxide
S2-
sulfide
N3-
nitride
P3-
phosphide
Writing the Chemical Formula
• Step 1: Write the symbols of the elements,
with the metal on the left-hand side and the
non-metal on the right-hand side.
Mg
Cl
• Step 2: Add the ionic charge of each ion
above the symbol
+2
-1
Mg
Cl
• Step 3: Determine the number of ions
required to bring the charge to zero.
1(+2) + 2(-1) = 0
Mg
Cl
• Step 4: Write the chemical formula using the
(red) coefficients in front of each bracket as
subscripts
Mg1Cl2
Note: Do not write the subscript “1”
The chemical formula for magnesium chloride is
MgCl2
Crisscross Method
• Step 1: Write the symbols of the elements
and their ionic charges
Mg 2+
Cl• Step 2: Crisscross the numbers of the ionic
charges so that they now become subscripts
Mg 2+
ClMgCl2
Multivalent Metals
• Some metals have multiple ionic charges.
E.g. Write the chemical name of CuBr2.
• Copper could have either +1 or +2
• Each bromide ion has a charge of -1, so the total
charge of bromide ions is 2(-1).
• The ionic charge of copper in this compound is +2
• Roman numerals are included ONLY if the metal
has more than one ionic charge.
• The name of CuBr2 is copper (II) bromide
Practice!