Transcript Elements and Compounds - La Salle College High School

Ionic
Compounds
Metals Vs. NonMetals
Metals
• Left of steps on
Periodic Table
• 80 percent of elements
are metals
NonMetals
• Right of steps
• 20 percent
– Pie chart on page 36
• Properties
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–
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Luster
Conductivity
Malleable
Ductile
• Properties
– May lack luster
– Do not conduct
• Except carbon
– Brittle
Electron Configuration
• The properties of metals and nonmetals
are greatly influenced by the electron
configurations of atoms.
Ionic Compounds
• Atoms may gain or lose electrons thereby
becoming ions.
– Cation
– Anion
Positive Charge
Negative Charge
• Why might a certain Ion gain rather than
lose electrons?
Electron Configuration
• Number of electrons in the outermost shell
is key.
• Few electrons  Tend to lose them
• Close to full Shell  Tend to gain
• Tendency towards stability
Compounds and Ionic Bonding
• A compound is a substance which is made
of two or more kinds of atoms or ions
which have joined together.
• Attractive force between positive and
negative ions creates Ionic Compounds.
• NaCl
Na+
Cl-
• The force of attraction between the
positive and negative ions is known as an
Ionic bond.
IMPORTANT
• When we talk about stability we are
referring to the number of electrons in the
valence shell.
Review
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Atom
Ion
Cation
Anion
Why does an atom lose or gain electrons?
Predictions
– Fluorine, Potassium, Lithium
• How many Chloride ions bond with Magnesium
ions?
Forming Ionic Compounds (Salts)
• Ionic bonds form
between METALS
and NONMETALS
when Electrons are
transferred (lost or
received).
• Columns 1,2,13 may
transfer with columns
15,16,17.
Forming Ionic Compounds
• Electrons get
transferred as a
result of energy input.
This may also occur
when materials are
placed in solution.
• A variety of
combinations are
possible depending
on the valence
electron number.
Atom gained one
electron. It now has
a negative charge.
This atom lost one
electron and now has
a positive charge.
Ionic Bonds
• An ionic bond is the attraction between a
positively charged cation and a negatively
charged anion.
Metals in columns
NonMetals in
1, 2, 3 are electron
columns 5, 6, 7
donors.
receive Electrons.
Which Elements form Ionic Bonds?
• The central idea (for the 50th time) is that
electrons, one or more, are transferred
between the outer shells of adjacent
atoms. This Creates Ions/Charged Atoms.
• Metals and NonMetals.
• Certain Elements may donate or receive
more than one electron. It can therefore
bond with multiple elements.
Example #1 Na and Cl
• How many valence electrons does each atom
have?
• Which atom will tend to Receive e-? Donate?
• What is the charge on each ion?
• What will the ratio between Na and Cl be?
Example #1 Na and Cl
• Sodium would lose one electron and
become positively charged, while Chlorine
would gain one electron becoming
negatively charged.
• The positive/negative charge attraction
would hold the two ions together.
Example #2 Mg and O
• How many valence electrons does each atom
have?
• Which atom will tend to Donate e-? Receive?
• What is the charge on each ion?
• What will the ratio between Mg and O be?
Example #2 Mg and O
• The Magnesium would lose two electrons,
becoming +2 charged and the Oxygen
would gain the two electrons becoming
-2 charged in the process.
• The negative/positive charge attraction
(+2/-2) (four times as much as +1/-1)
would hold the two ions together.
Example #3 Mg and Cl
• How many valence electrons does each
atom have?
• Which atom will tend to gain e-? Donate?
• What is the charge on each ion?
• What will the ratio between Mg and Cl be?
Example #3 Mg and Cl
• The Magnesium would lose two electrons,
becoming +2 charged and two chlorines
(not one) would each gain one electron,
each becoming -1 charged in the process.
• The three atoms would bond to each other
by the positive/negative attraction between
the ions.
Naming Ionic Compounds
• The same as naming individual ions.
• Cation, Electron Donor, or Metal in
compound is said first.
• Anion name is changed to …….ide and
said second.
Examples
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Sodium Chloride
Magnesium Oxide
Lithium Nitride
Potassium Bromide
Using the correct Name
1) K2S
7) SrS
2) LiBr
8) Al2O3
3) Sr3P2
9) MnO
4) BaCl2
10) ZnO
5) NaBr
11) ZnCl2
6) MgF2
12) Cu2O
Notation
Ionic Notation
• 3 Na+1
• 1 PO4-3
Ionic Compound Formula
• NaCl
• CaCl2
• Na3(PO4)
Formulas
Rules for Writing Formulas
• Metallic Donor is always written first.
• Nonmetallic Receiver is written second.
• Write the number of atoms required to
balance the formula as subscripts after the
element in compound.
– NaCl
– MgO
– MgCl2
The Ionic Compound
NaCl
Writing & Naming
Ionic Compounds
+1
Na
&
-1
Br
Writing & Naming
Ionic Compounds
+2
Ca
&
-1
Br
Writing & Naming
Ionic Compounds
+1
K
&
-2
O
Writing & Naming
Ionic Compounds
Li
?
& N
?
HW: Write the Name of the Compound
1) MgS
7) KBr
2) Ba3N2
8) FeO
3) NaI
9) SrF2
4) Li2S
10) CaO
5) Na3P
11) Al2O3
6) KCl
12) Fe2O3
HW: Write the Correct Formula
1) Magnesium Oxide
2) Lithium Bromide
3) Calcium Nitride
4) Sodium Sulfide
5) Copper (I) Sulfide
6) Copper (II) Sulfide
Practice Exercise #1
1.
2.
3.
4.
Which will donate, Which will receive?
How many will be donated/received?
Write the Ionic Notation of each.
Write the formula for each of the following.
– Lithium Oxide
– Potassium Chloride
– Sodium Nitride
– Calcium Chloride
– Magnesium Sulfide
– Barium Nitride
– Aluminum Fluoride
– Aluminum Oxide
– Aluminum Nitride
Diagramming Ionic Compounds
• Lewis Structures
– Diagram valence shell.
• Place valence electrons around nucleus
as they would be according to the octet
rule
Diagramming Ionic Compounds
Na
Cl
+
Na
Cl
Practice Exercise #2
• Diagram the following Ionic Compounds:
– Lithium Oxide
– Potassium Chloride
– Sodium Nitride
– Calcium Chloride
– Magnesium Sulfide
– Barium Nitride
– Aluminum Fluoride
– Aluminum Oxide
– Aluminum Nitride
Transition Metals
• d block elements that can form more than
one kind of ion.
• Lose electrons
• Why can they lose different numbers of
electrons?
• Copper
– Cu I or Cu II
• Iron
– Fe II or Fe III
Implications
• Copper and Iron as well as other transition
metals can form multiple ionic compounds.
Polyatomic Ions
• Compound Ions
• A group of COVALENTLY bonded atoms
that have a net charge (anion or cation)
• Most, but not all are Anions.
Polyatomics
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SO4-2
SO3-2
NO3-1
NO2-1
CO3-2
CN-1
OH-1
NH4+1
Sulfate
Sulfite
Nitrate
Nitrite
Carbonate
Cyanide
Hydroxide
Ammonium
Na3PO4
Na
P
O
PO4-3
O
O
P
O
Phosphate can
accept 3 electrons.
O
When it
does it has
a negative
3 charge.
It is therefore
called a………..
Sodium
Phosphate
O
Na
O
P
O
Na
Na3PO4
O
Na
Practice Exercise #3
Give the Ionic Notation and Formula for each.
– Potassium Sulfate
– Magnesium Sulfite
– Aluminum Nitrate
– Sodium Nitrite
– Lithium Carbonate
– Sodium Cyanide
– Barium Hydroxide
– Ammonium Chloride
– Ammonium Hydroxide
Draw/Diagram Magnesium Sulfite
Practice Exercise #4
• Write out the Ionic Notation, Formula and
Names of the following ionic compounds:
– Li and F
– Na and S
– K and Br
– Rb and O
– Ca and Cl
– Mg and SO3-2
– Al and NO3-1
- Na and CO3-2
- Li and OH-1
- NH4+1 and Cl
- Ca and SO4-2
- NH4+1 and OH-1
- Na and CN-1
- NH4+1 and SO4-2