Covalent Bonds
Covalent Bond - form of chemical bonding that is characterized by the sharing of pairs of electrons between atoms.
Generally between two or more non metals
Molecules – A group of atoms which are covalently bonded together, which is electrically neutral.
Ionic Bond – form of chemical bonding that is characterized by a cation and anion attraction resulting from the
transfer of electrons, generally between a metal and a nonmetal.
Formula Unit – Lowest whole number ratio of cations and anions in an ionic crystal
Formula
Lewis Dot
Formula
O2
SO2
N2
NI3
F2
CO2
CBr4
SiO2
CS2
H 2O
PI3
H2
HF
SiBr4
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Lewis Dot
Some of the Combinations for Molecular Shapes
V.S.E.P.R. – Valance Shell Electron Pair Repulsion Theory. States that electron pairs REPEL other electron pairs, resulting in a
predictable molecular shape. All electron pairs will be located at the maximum distance apart from the other
electron pairs.
Shape
Molecular Model
1. Linear with 2 elements
2. Linear with 3 elements
No Spare electrons on the central atom
3. Bent w/single bonds
2 sets of spare electrons
on the central atom
4. Bent w/a single and double bond
1 set of spare electrons
on the central atom
5. Trigonal Pyramidal
1 set of spare electrons
on the central atom
6. Trigonal Planar
No set of spare electrons
on the central atom
7. Tetrahedral
4 Bonds on the central atom
No spare electrons on the
2
central atom
Covalent Shapes Worksheet
Molecule
Lewis Dot Structure
# Electron
Pairs on
Central Atom
Bonding:
NH3
Nonbonding:
Bonding:
SeO
Nonbonding:
Bonding:
BF3
Nonbonding:
Bonding:
CF4
Nonbonding:
Bonding:
CH4
Nonbonding:
Bonding:
H2
Nonbonding:
Bonding:
SBr2
Nonbonding:
Bonding:
CHFBr2
Nonbonding:
3
3D Sketch of Model
Name of Shape
Lewis Dots, Shapes and Names WS
Directions – Draw the Lewis Dot Structure for the Molecules Below. Draw and Name the Molecular Shape.
Formula
Shape
Formula
O2
SF2
N2
NI3
F2
CO2
CBr4
SiO2
CS2
H 2O
PI3
H2
HF
SiBr4
4
Shape
Rules & Prefixes Used For Naming Binary Covalent Compounds
Part 1: Name the Prefix
Prefix
MonoDi-
Rules
1.
2.
3.
Number
1
2
3
4
5
Prefix
Number
6
7
8
9
10
The last element end in –ide
Prefixes are used on both elements, but mono- is not used on the first element
If it is a diatomic molecule, ex, O2, use the name of the element. (BrINClHOF)
Ex: PCl5 is phosphorous pentachloride, not monophosphorous pentachloride
Part 2: Name the Following Binary Covalant Compounds/Molecules
1. CS2 = ________________________
15. CO2 = ________________________
2. SF6 = ________________________
16. I2 = __________________________
3. N2 = _________________________
17. BI3 = _________________________
4. HF = _________________________
18. PBr3 = ________________________
5. CBr4 = _______________________
19. H2O= ________________________
6. SiO2 = ________________________
20. SbF5= ________________________
7. N2O2 = _______________________
21. SO3= ________________________
8. F2 = __________________________
22. XeF4= ________________________
9. PCl3 = ________________________
23. CSi2=_________________________
10. IF5 = _________________________
24. SO=__________________________
11. NO = ________________________
25. SO2=_________________________
12. CI4 = _________________________
13. P4S3 = ________________________
14. CO = _________________________
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Covalent Naming and Formulas
Write the names for the following covalent compounds:
1.)
P4S5 __________________________________
2)
O2 __________________________________
3)
SeF6 __________________________________
4)
Si2Br6 __________________________________
5)
SCl4 __________________________________
6)
CF4 __________________________________
7)
B2Si __________________________________
8)
NF3 __________________________________
9)
CO
10)
CO2
11)
H2O
11ª).
Cl2O7 _________________________________________
(use formal name, not water)
Write the formulas for the following covalent compounds. Numbers must be written as SUBSCRIPTS.
Element symbols must be written correctly:
12)
antimony tribromide __________________________________
13)
hexaboron monosilicide __________________________________
14)
chlorine dioxide __________________________________
15)
carbon monoxide __________________________________
16)
iodine pentafluoride __________________________________
17)
dinitrogen trioxide __________________________________
18)
ammonia (also known as nitrogen trihydride) __________________________________
19)
phosphorus triiodide ____
20)
carbon tetrachloride
21)
trisulfur hexafluoride
22)
nitrogen dioxide ____________________________________________________
23)
sulfur hexafluoride __________________________________________________
.
_
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Polar & Non Polar Bonds & Molecules
Nonpolar Bond – Covalent bond where the electrons are shared. Difference in EN values is 0.0-0.4
Polar Bond – Covalent bond where the electrons are shared unevenly, resulting in small positive and negative charges on the
atoms involved. The more electronegative element pulls electrons towards itself. Difference in EN values is 0.4-2.0
Ionic Bond – Chemical bond where the Difference in EN values is >2. It is similar to a Polar Covalent Bonds but much more
severe. The extreme difference in EN value results not in the sharing of electrons, but rather a taking of electrons.
Polar Molecule – This is an entire molecule that has a positive and/or negative side.
Nonpolar Molecule – Molecule which does not have a positive and/or negative side.
Directions: Complete the Table Below.
Name the
Molecule
Lewis Dot
Name the Shape & Draw the
Shape
H2O
EN
Difference
Name it:
H=2.2
O=3.4
SI2
Name it:
S=2.6
I=2.7
CF4
Name it:
C=2.5
F=4.0
CH3Br
C=2.5
H = 2.2
Br=3.0
Name it:
CaO
Name it:
Ca=1.0
O=3.5
BI3
Name it:
B = 2.04
I = 2.66
NBr3
Name it:
N=3.04
Br=2.96
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Type of Bond
NPC/PC/I
P/NP
Molecule
Polar & Non Polar Bonds & Molecules
Name the
Molecule
Lewis Dot
Name the Shape & Draw the
Shape
EN
Difference
NF3
Name it:
N=3.0
F=4.0
BF3
Name it:
F= 3.98
B= 2.04
BH2F
F= 3.98
B= 2.04
H = 2.2
Name it:
HF
Name it:
H=2.2
F=4.0
MgF2
Name it:
Mg = 1.2
F = 4.0
N2
Name it:
N=3.0
O2
Name it:
O =3.5
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Type of Bond
NPC/PC/I
P/NP
Molecule
Name
Molecule
&
Polarity
Covalent Review
EN
Name the Molecule
Individual Bonds
NPC, PC or I
Lewis Dot Structure
Include All Valance Electrons
Name the Shape
Si = 1.9
SiBr4
Br = 3.0
H = 2.2
H2S
S = 2.5
N = 2.2
NBr3
Br = 3.0
P = 2.2
PI3
I = 2.7
C = 2.6
CO2
BF3
O2
1.
O = 3.4
B = 2.0
F = 4.0
O = 3.4
Define Covalent Bond:
2. What does “Polar” mean?
3. Explain the difference between a polar covalent BOND and a non polar covalent BOND
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Draw the Shape
4. What is the difference between a polar bond and a polar molecule?
5. Why is it possible to have Polar Bonds, but not a Polar Molecule?
6. In a polar covalent bond, where do the electrons move?
6a. Which are POLAR molecules?
H2O, BH3, CH3F, CF4, NH3, NF3, CH4
7. What is the VSEPR theory and what does it explain?
8. Based on EN values, which elements will combine to have the most ionic character?
F = 4.0, O = 3.4, C = 2.6, Mg = 1.2
9. In a Lewis Dot Structure, the central atom is the atom with the
a.
Fewest e-,
b. Lowest EN, c. Highest Atomic #, d. Highest mass, e most radioactive, f. Needs the most e-
10. Which substance has 3 single covalent bonds?
CO2
N2
F2
11. All the bonds below are polar, but which molecules
are polar?
CH4 BF3 H2O CO2 HF
O2 NH3
12. Which substance is NOT Covalent?
13. Covalent Substances are primarily between:
H2O, NaCl, SiF4, NBr3, MgO
14. Which substance(s) have one double bond?
CO2
N2
F2
15. Which substance(s) have a triple bond?
O2 NH3
CO2
N2
F2
O2 NH3
16. Name S3Br6
17. Name C4F8
18. Name H2O
19. Name CO
20. Name N2I5
21. Name S4Br8
22. Name I2
23. Name SF6
1
0
Name
Molecule
&
Polarity
SiBr4
NPM
H2S
PM
NBr3
NPM
PI3
NPM
CO2
NPM
BF3
NPM
Covalent Review
EN
Name the
Molecule
Individual
Bonds
NPC, PC or I
Lewis Dot Structure
Include All Valance Electrons
Name the Shape Draw the Shape
Si = 1.9
Br = 3.0
H = 2.2
S = 2.5
N = 2.2
Br = 3.0
P = 2.2
I = 2.7
C = 2.6
O = 3.4
B = 2.0
F = 4.0
O2
O = 3.4
NPM
2. Define Covalent Bond:
2. What does “Polar” mean?
3. Explain the difference between a polar covalent BOND and a non polar covalent BOND
1
1
4. What is the difference between a polar bond and a polar molecule?
5. Why is it possible to have Polar Bonds, but not a Polar Molecule?
6. In a polar covalent bond, where do the electrons move?
6a. Which are POLAR molecules?
Electrons move towards the more electronegative element
H2O, BH3, CH3F, CF4, NH3, NF3, CH4
7. What is the VSEPR theory and what it explain?
8. Based on EN values, which elements will combine to have the most ionic character?
F = 4.0, O = 3.4, C = 2.6, Mg =
9. In a Lewis Dot Structure, the central atom is the atom with the
b. Fewest e-,
b. Lowest EN, c. Highest Atomic #,
10. Which substance has 3 single covalent bonds?
CO2
N2
F2
O2
NH3
12. Which substance is NOT Covalent?
H2O, NaCl, SiF4, NBr3,
N2
F2
O2
11. All the bonds below are polar, but which molecules are
polar?
CH4 BF3 H2O CO2 HF
13. Covalent Substances are primarily between:
MgO
14. Which substance(s) have one double bond?
CO2
d. Highest mass, e most radioactive, f. Needs the most e-
15. Which substance(s) have a triple bond?
NH3
CO2
N2
F2
O2
NH3
16. Name S3Br6
17. Name C4F8
18. Name H2O
19. Name CO
20. Name N2I5
21. Name S4Br8
22. Name I2
23. Name SF6
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