Bonding.
Quarter 1 Unit 2
What is bonding?
Atoms join to form molecules because atoms like to
have a full valence (outer shell) of electrons (usually
means 8).
Ionic bond- give up electron completely.
Covalent- share electrons.
Ionic Bonds
The taking or giving of electrons.
Ionic Bonds
Metals typically give up electrons, which makes them
become more______. What are these ions called?
Nonmetals typically gain electrons, which makes them
become more_______. What are these ions called?
Give up or take electrons from each other.
What holds them together in a bond?
INDIVIDUAL
Ionic Bonds
If atoms transfer e- to create opposite ions,
the opposite charges attract and form an
ionic bond
Na
Cl
Na
[video]
Cl
Coulomb’s Law
How can we calculate the
attractive force?
+q =magnitude of the
positive charge.
-q=magnitude of the
negative charge.
r=distance between the
charges.
Let’s experiment with is
equation…
Say an element has a positive charge of three and another
element has a negative charge of three. They are 3 away from
each other. What is the overall attraction?
Now say a different element has a negative charge of 6 and
another element has a positive charge of 6. They are still 3
away from each other. What is the overall attraction?
Attraction increases as charges increase.
What about the distance? What happens when the
denominator increases?
Checking for understanding
What is the attractive force of table salt?
Na has a charge of +1 and Cl has a charge of -1.
They are 103 pm (picometers) units away from each
other.
Complimentary Elements
Ignore the transitional metals.
Identify how many valence electrons the element has.
Would this element want to gain or lose an electron?
Which element compliments it?
So…
Which element would Li
prefer to bond with?
Which element would S
prefer to bond with?
Rules for Naming Binary Ionic
Compounds
Rule 1: The cation is written first in the name; the
anion is written second in the name.
Rule 2: The name of the cation is the same as the
neutral element from which it is derived.
Rule 3: The anion is named by adding the suffix –ide
to the root of the element name.
Example: NaI is named sodium iodide.
Check Point
MgO
Rb2Se
Calcium Sulfide
Sodium Oxide
The Sharing of Electrons
Covalent Bonds
Break down the word: Co-valence.
Two atoms share electrons.
Each counts the shared electrons as part of their
valence shell.
The number of covalent bonds an atom can form is the
same number of electrons in its valence shell.
Covalent Bonds
If e- are shared between atoms, then atoms
are connected by a covalent bond
[board]
[video]
Catalyst
Draw the Lewis dot structures
and find the ionic form of these
elements:
Na
Mg
S
Cl
Drawing Lewis Dot Structures
Look up the number of valence electrons for a particular
element.
Draw the electrons in a circular motion around the element.
Each side of the element’s symbol receives up to 2 electrons.
Fill in the outer most sides first.
Circle the shared lone pairs.
Replace replace circles with bonds.
Count to make sure everyone is satisfied with 8 valence
electrons.
Covalent Bonds Examples
Use Lewis Diagrams to Show the Resulting
Covalent Bonds
Cl, Cl
C, H, H, H, H
C, O, O
How to Name Binary Covalent
Compounds
The first element in the
compound keeps its
neutral name.
The second element
changes its ending to –
ide.
Whenever there are more
than one of an element
you add the correct prefix
to the beginning of the
elements name.
Examples
CO2
P4O10
Sulfur trioxide
Dinitrogen tetraoxide
Checking for Understanding
FeO
SrI2
What type of bond will
form?
What type of bond will
form?
What is the chemical name
for this compound?
What is the chemical name
for this compound?
H2 O
Cs2S
What type of bond will
form?
What type of bond will
form?
What is the chemical name
for water?
What is the chemical name
for this compound?
Predicting Bonding
When will a ionic bond
occur?
When will a covalent bond
occur?
When a Nonmetal and a
metal are involved.
When two nonmetals are
involved. With the
exception of MnO2 or
manganese dioxide.
Ionic or Covalent?
Ionic bonds form between a metal and a
nonmetal and involve a transfer of e-
Covalent bonds form between 2 nonmetals or a non-metal and hydrogen and
involve sharing e-
Covalent or Ionic?
Na and Cl
IONIC
C and H
COVALENT
C and S
COVALENT
N and N
Ca and S
Fe and Cl
COVALENT
IONIC
IONIC