SmartStarter What is the octet rule SmartStarter Draw the electron dot diagram for ionic compound MgCl 2 Compare Eyes on Chemistry Epsom Salts Rock Salt Sucrose One more WHAT DO YOU NOTICE ABOUT THEIR STRUCTURE ID: 932569
Download Presentation The PPT/PDF document "Chemical Bonds Chapter 6" is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
Slide1
Chemical Bonds
Chapter 6
Slide2SmartStarter
What is the octet rule?
Slide3SmartStarter
Draw the electron dot diagram for ionic compound MgCl
2
Slide4Compare – Eyes on Chemistry
Epsom Salts
Rock Salt
Sucrose
One more…
WHAT DO YOU NOTICE ABOUT THEIR STRUCTURE?
Slide5NaCl
Slide6Valence Electrons and Lewis Dot Structure
(AKA Electron Dot Diagram)
Remember
: Octet Rule? Valence Electrons?
How many valence electrons in…
Example: Sulfur
Your turn 1-20 – count off!
Slide7Stable Electron Configurations
Slide8Stable Electron Configurations
Slide9Stable Electron Configurations
Slide10Stable Electron Configurations
Slide11Stable Electron Configurations
Slide12Stable Electron Configurations
Slide13Stable Electron Configurations
Slide14Stable Electron Configurations
Slide15Stable Electron Configurations
Slide16Where we are going from here…
Chemical Bonds
Ionic, Covalent, Metallic
Slide17Ionic Bonding
Relationships are weaker when you
take/borrow/steal
…
It means someone had to
give/lend/be robbed
…Where the analogy breaks down…
Who is left feeling more
negative
?
Who is more positive?
What happens when negatives and positive are near each other?
Slide18Ca+ion vs. Anion
Slide19Oxidation #
- Can you predict which elements will form ionic bonds with which?
- Which groups with which groups?
- Metals with Metals? Metals with Non-metals?
Slide20MgCl
2
Lattice shape depends on the arrangement of the atoms.
2 Factors:
Size of atoms
and
ratio of elements
RATIO = 1:2
Slide21Slide22IONIC BONDS
Slide23Electronegativity
What are the periodic trends with electronegativity?
Slide24Slide25Electronegativity
SMARTStarter
:
What kind of bond forms between sodium and fluorine?
Slide26Covalent Bonding (6.2)
Three fish
Relationships are stronger when you
share
Bond Strength:
Covalent bond
>
Ionic bonds
One pair of shared electrons?
Two pairs of shared electrons?
Three pairs of shared electrons ?
Slide27Molecules
= ? - Define it!
Electron
D
ot
D
iagram of Covalent Bonds –
Dr. B - Practice
Slide28Polar
Covalent Bond
EXAMPLE: Water
Share…but not equally
Results in partial charges = polarity
Slide29Non
polar or PURE Covalent Bonds
Carbon
dioxide
(CO
2
)
Formula
:
CH
4
Geometry
Symmetry
Name:
Methane
Shape Matters!
N
ame
Formula
Slide30Molecular Compound
– bonded molecules
Forces of attraction that hold molecules together in a liquid or solid
- Stronger in polar or nonpolar molecules?
Ex.
Hydrogen bonds
(
Van der Waals Forces
)
Slide31-
ite
and -ate
Some
polyatomic anions
contain oxygen
.
When
an element
forms two oxygen containing anions they are named with different suffixes/endings:
-ite =
the
one with less oxygen
-
ate
=
the
one with more
oxygen
Examples:
NO
2
-
Nitrite
NO
3
-
Nitrate
SO
3
2-
Sulfite
SO
4
2-
Sulfate
POLYATOMIC IONS:
A
polyatomic ion
, also known as a molecular
ion
, is a charged chemical species (
ion
) composed of two or more atoms covalently bonded or of a metal complex that can be considered to be acting as a single unit. The prefix poly- means "many," in Greek, but
even
ions
of two atoms are commonly referred to as
polyatomic
Slide32Nomenclature
--
How
do you name or talk about compounds and molecules?
Formulas
- describes the ratio of ions in the
compound
Name
– words to describe/identify it.
Binary compound =
exactly two different elements Metal + Nonmetal = ?
Nonmetal + Nonmetal = ?
Metal + Metal = ?
Carbon
dioxide
(CO
2
)
N
ame
Formula
Examples:
calcium
chloride (CaCl
2
), sodium fluoride (
NaF
), and magnesium oxide (
MgO
)
water
(H
2
O), and sulfur hexafluoride (SF
6
)
Slide33Talking
Ionically
…
Formula
When writing an
ionic
FORMULA
between a
metal
and a
nonmetal follow these 5 steps
:
Write
the symbols for the metal and the nonmetal.
Write the valences as superscripts above each symbol.
Drop the + and - sign.
Crisscross the valences so they become the subscript for the other element.
Reduce subscripts whenever possible. Only when both are divisible by a number greater than one.
Slide34SmartStarter
Show me how…
Slide35Show me how…
Slide36Slide37-ide
The
-ide
ending is added to the name of a monoatomic ion of
an
element
.
H- Hydride F- Fluoride O
2- Oxide S2- Sulfide
N
3-
Nitride
P
3-
Phosphide
Ionic Compounds - Naming of
anions
Pattern/Rules for
Naming Ionic Compounds
:
NAME
…
name of cation
+
name of anion
+ “
-ide
”
Slide38Practice
Using a periodic table
& oxidation numbers find the formula and name of these ionic compounds:
magnesium and fluorine
aluminum and sulfur
Nitrogen and calcium*
b
arium
and iodine
b
romine and potassium*
aluminum
and phosphorus
strontium and oxygen
nitrogen and magnesium*
cesium
and phosphorus
Check your answers
Slide39When the
metal
(
ca+ion
) is a
Transition Metal
…
More than one type of ions possible
A Roman numeral in parentheses,
following the name of the element, is
used for elements that can form more than one positive ion. This is usually seen with metals. You can use a chart
to see the possible valences for the elements
.
Fe
2
+
Iron (II)
Fe
3+
Iron (III)
Use Roman Numerals to indicate the charge
Ex. Copper (II) ion + Chlorine
Cu
2+
+
__
Cl
-
CuCl
?
-
ous
and -
ic
Although Roman numerals are used to denote the ionic charge of
cations
, it is still common to see and use the endings
-
ous
or
-
ic
. These endings are added to the Latin name of the element (e.g.,
stannous
/
stannic
for tin) to represent the ions with lesser or greater charge, respectively. The Roman numeral naming convention has wider appeal because many ions have more than two valences
.
Fe
2
+
Ferrous
Fe
3+
Ferric
Cu
+
Cuprous
Cu
2+
Cupric
Cu
+
Copper (I)
Cu
2+
Copper (II)
Slide40Write the names of the possible valences of Chromium. How would Chromium (III) and Oxygen bond? (Give the name and formula).
Slide41Practice
Using a periodic table try these then check your answers
.
iron(III) and phosphorus
copper(II) and fluorine
silver(I) and sulfur
manganese(II) and nitrogen
lead(IV) and iodine
copper(II) and bromine
gold(II) and phosphorus
lead(IV) and oxygen
silver(I) and nitrogen
copper(II)
chloride
Check your answers
Slide42Compounds containing
POLYATOMIC IONS
When you write formulas for compounds containing a polyatomic ion:
Write the symbols for the metal and the polyatomic ion.*
Write the valences as superscripts above each.
Drop the + and - sign.
Crisscross the valences so they become the subscript for the other element.
If you have more than one of the polyatomic ion, you must encase it in
parenthesis
and place the subscript outside.
You can only reduce a subscript outside the parenthesis of a polyatomic ion - you cannot change the formula the polyatomic ion
.
*In the case of ammonium (the only polyatomic
cation
) you would write it first and then the anion
Polyatomic Ion
:
covalently bonded group of atoms that has a positive or negative charge and acts as a unit
Slide43Let me show you…
Slide44Let me show you…
Slide45Practice…You show me!
Try these using a periodic table
and
a list of polyatomic ions
.
aluminum and sulfate
ammonium and sulfur
barium and hydroxide
magnesium and phosphate
lead(IV) and sulfite
strontium and carbonate
zinc(II) and phosphate
ammonium and oxygen
calcium and nitrate
tungsten(II) and sulfate
Check Answers
Slide46Covalent (Molecular) Compounds
Slide47COVALENT
FORMULAS
:
TWO NONMETALS
Here are six covalent compounds that form between nitrogen and oxygen:
nitrogen
monoxide =
NO
nitrogen
dioxide =
NO2
dinitrogen
oxide =
N
2
O
dinitrogen
trioxide = N
2
O
5
dinitrogen
tetroxide =
N
2
O
4
dinitrogen
pentoxide
=
N
2
O
5
Because covalent compounds share electrons they can share in different ways and can form many compounds between the same two elements.
IMPORTANT:
You never crisscross valences to determine covalent (two nonmetals) formulas.
So
just how do you write the formulas?
Prefixes
- that's how.
Slide48NAMES
*Lowest electronegativity goes first or Left to right on the P-Table
Slide49Practice
–
GIVE THE FORMULA
Go
ahead and try these:
sulfur dioxide
dihydrogen
oxide
phosphorus
pentafluoride
carbon tetrachloridealuminum
trichloride
Check your answers
Just look at the name and you have the formula for a covalent compound!
Slide506.4 Metallic Bonds
From this video you should learn:
How they form….common pool of electrons
Metallic Lattice structure ?
How they give metal its strength…?
Alloys…combined properties
Slide51Kinesthetic Learning: Bonding Charades
Four Types of Bonds = four possible answers
Ionic Bonds
Pure Covalent Bond
Polar Covalent Bond
Metallic Bonds
Procedure:
Form your group of 6-8
Get your assignment
3 minutes to plan your skit
Perform when called on
GROUP WHO IS IDENTIFIED FASTEST FOR EACH CATEGORY GETS A PRIZE!
RULES:
No noise
No letters/words/numbers/Symbols
Slide52Metallic Bonds
Bond
that keeps metal atoms together is called
metallic bond
. In metals;
Number of valence electrons is smaller than number of valence orbitals. So, they have
many empty valence orbitals
.
Their ionization energies are small and they are weakly attracted by nucleus.
Valence electrons of metals can jump to the other atom's valence orbitals. This
free movement of electrons makes metals good conductor of electricity and heat. All valence electrons of metals can behave like this.
P-TABLE TRENDS
In
periodic table, as we go from top to bottom in metal group, strength of metallic bond and melting point decrease.
In periodic table, as we go from left to
rşght
in same period, strength of metallic bond and melting point increase.
Slide53Lab IDEA
Chemical Bonding Lab (The name’s Bond, Covalent Bond.)
Chemical bonding lab?! This sounds like fun! Or we could just wash test tubes and tin can lids for the first half hour of class. You know, either one would be fine.
What types of elements make up your compounds? (Be specific and list this by compound.)
Calcium chloride-
calcium (metal), chlorine (nonmetal)
Potassium iodide-
potassium (metal), iodine (nonmetal)
Sodium chloride-
sodium (metal), chlorine (nonmetal)
Citric acid-
carbon (nonmetal), hydrogen (nonmetal), oxygen (nonmetal)
Phenyl salicylate-
carbon (nonmetal), hydrogen (nonmetal), oxygen (nonmetal)
Sucrose-
carbon (nonmetal), hydrogen (nonmetal), oxygen (nonmetal)
Which atoms in your compounds have high ionization energy? Low ionization energy? High electronegativity? Low electronegativity?
Calcium, potassium, and sodium all have relatively low
electronegativities
and ionization energies, while chlorine, iodine, carbon, hydrogen, and oxygen all have relatively high
electronegativities
and ionization energies.
There’s a scale for bond type based on electronegative differences
here
(it’s from Quinnipiac University). Determine the bond type of each compound you used today using the electronegativity values on page 161 in your book.
Calcium chloride-
ionic (metal/nonmetal)
Potassium iodide-
ionic (metal/nonmetal)
Sodium chloride-
ionic (metal/nonmetal)
Citric acid-
covalent (nonmetal/nonmetal)
Phenyl salicylate-
(nonmetal/nonmetal)
Sucrose-
(nonmetal/nonmetal)
Which compounds were ionic? Which covalent?
The calcium chloride, potassium iodide, and sodium chloride are all ionic, while the citric acid, the phenyl salicylate, and the sucrose are all covalent.
What properties are associated with ionic compounds? What properties are associated with covalent compounds?
Ionic compounds have very high melting and boiling points, are soluble in water, and almost always conductive when dissolved in a solution or melted.
Covalent compounds have low melting and boiling points (they melted almost immediately)
a
nd did not conduct electricity, although the citric acid did, it was not as bright as the other compounds.
Ionic compounds have very high melting and boiling points, are soluble in water, and almost always conductive when dissolved in a solution or melted.
Covalent compounds have low melting and boiling points (they melted almost immediately) and
low conductivity.
Sugar dissolves
Salt dissolves
Slide54MORE Practice/Review
Quia.com
Slide55POLYATOMIC ION
: A covalently boned group of atoms that has a positive or negative charge and acts as a unit … ex. Iron (III) Oxide Fe(OH)
3
Slide56Electronegativity
Slide57HOW DO THE ELECTRON CONFIGURATIONS CHANGE?
ACROSS THE SAME PERIOD?
DOWN THE SAME GROUP?
Slide58R
adius of the atom
Radius of an ion of the atom
Charge of the ion (# electrons
l
ost/gained)
HOW DOES THE RADIUS OF AN ATOM CHANGE WHEN IT BECOMES AN ION?
How does the radius change…
When it becomes a
cation
?
When it becomes an anion?
Predict the radius change and # of valence electrons for Francium (
Fr
)
Slide59hypo- and per-
In the case where there is a series of four oxyanions, the
hypo-
and
per-
prefixes are used in conjunction with the
-
ite
and
-ate suffixes. The hypo- and per- prefixes indicate less oxygen and more oxygen, respectively. ClO-
HypochloriteClO2- ChloriteClO
3
-
Chlorate
ClO
4
-
Perchlorate
bi- and di- hydrogen
Polyatomic anions sometimes gain one or more H
+
ions to form anions of a lower charge. These ions are named by adding the word
hydrogen
or
dihydrogen
in front of the name of the anion. It is still common to see and use the older naming convention in which the prefix
bi-
is used to indicate the addition of a single hydrogen ion.HCO
3
-
Hydrogen carbonate or bicarbonate
HSO
4
-
Hydrogen sulfate or bisulfate
H
2
PO
4
-
Dihydrogen
phosphate
Not learned in this class….but interesting: