What is a covalent bond?
A covalent bond forms between two atoms that are
sharing one or more pair of electrons.
Usually occurs when the electronegativity difference
between the two elements is small (<1.7)
Covalent bonds form between two nonmetals.
The bond results from an overlapping of orbitals.
A covalent bond is a weaker bond than an ionic bond.
Properties of compounds resulting from a covalent
bond include: low melting point, gases or liquids at
room temp (some are soft solids), do not conduct
electricity, many are insoluble in water.
Naming covalently bonded
compounds.
The first element is named according to the element
name.
An –ide ending is added to the name of the second
element.
Numerical prefixes are used to indicate the number of
each type of atom present.
Numerical Prefixes
Prefix
Number
*Mono (only used with the second
element)
1
Di
2
Tri
3
Tetra
4
Pent
5
Hex
6
Hept
7
Oct
8
Non
9
Dec
10
Name the following compounds
CO2
CO
N2O
NO
NO2
N2O3
N2O4
N2O5
PCl5
PCl3
SF6
Write the formulas for the
following compounds:
Sulfur trioxide
Dioxygen difluoride
Tetraphosphorus decaoxide
Diboron trioxide
Arsenic pentafluoride
Silicon dioxide
Monohydrogen dioxide
Nitrogen trihydride
Types of Covalent Bonds
A single covalent bond occurs when one pair of
electrons (2 electrons) are shared between two atoms.
If the electrons are shared equally, it is called a
nonpolar covalent bond. (This type of bond only
occurs if the electrons are shared between identical
atoms)
If the electrons are shared unequally, it is called a polar
covalent bond.
Polar and Nonpolar Molecules
Molecules can also be polar and nonpolar.
Molecules are nonpolar if:
1) the bonds are nonpolar
2) the polar bonds are arranged symmetrically
Molecules are polar if the polar bonds are arranged
asymmetrically.
Lewis Dot Diagrams
Cl2
Linear
Nonpolar bonds
Nonpolar molecule
Chlorine
Lewis Dot Diagrams
H2O
Bent
Polar bonds
Polar molecule
Dihydrogen monoxide
Lewis Dot Diagrams
NH3
Trigonal pyramidal
Polar bonds
Polar molecule
Nitrogen trihydride
Lewis Dot Diagrams
CH4
Tetrahedral
Polar bonds
Nonpolar molecule
Carbon tetrahydride
In covalent compounds, atoms become
stable by ___ their valence electrons.
5%
95%
transferring
2. sharing
1.
A ___ covalent bond is the result of an
equal share of electrons by both atoms.
11%
89%
polar
2. nonpolar
1.
A cation has a ___ charge.
100%
0%
positive
2. negative
1.
When an atom ___ electrons, it becomes
positively charged.
5%
95%
gains
2. loses
1.
In the formula CO2, the number 2 is
called a ___.
0%
0%
0%
100%
superscript
2. oxidation number
3. charge
4. subscript
1.
What is the correct name for
PCl3?
0%
0%
100%
0%
Monophosphorus trichloride
2. Phosphorus chloride
3. Phosphorus trichloride
4. Traphosphorus chloride
1.
What is the correct name for
Li2O?
11%
37%
26%
26%
Lithium oxide
2. Dilithium oxide
3. Lithium (II) oxide
4. Lithium dioxide
1.
Which is not a diatomic
molecule?
11%
22%
11%
56%
Fluorine
2. Nitrogen
3. Bromine
4. Boron
1.
Which element is a nonmetal?
11%
0%
89%
0%
Boron
2. Lithium
3. Carbon
4. Magnesium
1.
Which element has 7 valence
electrons?
0%
0%
100%
0%
Boron
2. Nitrogen
3. Fluorine
4. Manganese
1.
Noble gases are stable because
they have __ valence electrons.
0%
0%
0%
100%
2
2. 4
3. 6
4. 8
1.
The noble gases are in which
block of the periodic table?
6%
61%
22%
11%
s
2. p
3. d
4. f
1.
Electrons have what charge?
84%
16%
0%
-1
2. +1
3. 0
1.
How many valence electrons are in an
atom of oxygen?
0%
0%
100%
0%
2
2. 4
3. 6
4. 8
1.
How many shared pairs are
present?
0%
100%
0%
0%
1
2. 2
3. 3
4. 4
1.
How many electrons are not
shared?
5%
26%
0%
68%
1
2. 2
3. 3
4. 4
1.
How many single bonds are
present?
5%
63%
0%
32%
1
2. 2
3. 3
4. 4
1.
Are the bonds polar or
nonpolar?
74%
26%
Polar
2. Nonpolar
1.
What is the shape of the
molecule?
21%
63%
0%
16%
Linear
2. Bent
3. Trigonal pyramidal
4. Tetrahedral
1.
Is the molecule polar or
nonpolar?
63%
37%
Polar
2. Nonpolar
1.
10 ml of the substance has a mass of 9 g.
What is its density?
79%
5%
16%
0%
0.9 g/ml
2. 1.0 g/ml
3. 1.1 g/ml
4. 19 g/ml
1.
What is the percent oxygen in
the substance?
11%
61%
22%
6%
11%
2. 33%
3. 67%
4. 89%
1.
Double and Triple Bonds
A double covalent bond occurs when two atoms share
two pairs (4 electrons) of electrons.
A triple covalent bond occurs when two atoms share
three pairs (6 electrons) of electrons.
Examples of compounds
consisting of double bonds.
CO2
O2
C2H4
Examples of compounds
consisting of triple bonds.
N2
HCN
C2H2
0
