Covalent Bonds Worksheet
Name_______________
How to draw Lewis Structures of Covalent Compounds
(Problems 1-6)
Example: What molecule would form from 1 Carbon atom and unlimited hydrogen atoms?
1.
Draw the lewis structure of a Carbon atom and a hydrogen atom.
2.
Create a covalent bond between the carbon atom and the hydrogen atom. All covalent bonds are
between 2 or more non-metals (no metals are needed). In a covalent bond, electrons are shared.
Therefore a single bond counts as 2 electrons for both the carbon and the hydrogen.
3.
Follow the octet rule. Atoms are unstable until they have a full outer shell of electrons. For H
and He, this means that they have 2 electrons. For all other elements, this means that they have 8.
For this reason, Noble Gases do NOT form covalent bonds.
Our Hydrogen now has 2 valence electrons and is “happy” according to the octet rule.
Our Carbon has 3 single electrons and a single bond for a total of 5 electrons. It is NOT “happy.”
4.
Bond more hydrogen atoms on to the carbon atom until all the hydrogen atoms have 2 valence
electrons and the carbon atom has 8 valence electrons.
5.
Rewrite the lewis structure of the molecule to make it look neat.
Simple Covalent Bonding: Draw the lewis structures of the following covalent compounds.
1.
2 carbon atoms and unlimited hydrogen atoms
2.
Bromine and Oxygen
3.
1 Nitrogen atoms and unlimited hydrogen atoms
4.
Oxygen and hydrogen
5.
1 sulfur atom, 4 oxygen atoms and unlimited hydrogen atoms
6.
Phosphorus and hydrogen (tricky)
Bond
How to draw Lewis Structures of
Covalent Compounds using Double and
Triple bonds (Problems 7-12)
Example: What molecule would form from 1 Carbon atom and unlimited
oxygen atoms?
Single
Number
of
electrons
it holds
2
Double
4
Triple
6
1.
Draw the lewis structure of a Carbon atom and an Oxygen atom.
2.
Always start with the carbon atom (if there is one). Carbon often forms the “central atom” of
covalent compounds. Create a covalent bond between the carbon atom and the oxygen atom. In a
covalent bond, electrons are shared. Therefore the carbon is now surrounded by 5 electrons and
the oxygen is now surrounded by 7 electrons. According to the octet rule, neither atom is
“happy.”
3.
Create another covalent bond between the carbon atom and another oxygen atom. In a covalent
bond, electrons are shared. Therefore the carbon is now surrounded by 6 electrons and both
oxygens are now surrounded by 7 electrons. According to the octet rule, none of the atoms are
“happy.”
If we add two more oxygens the carbon will be “happy” but none of the oxygens will be. So this is not
possible
4.
There is a way that we can satisfy both the oxygens and the carbon. If we take the one of the extra
electrons on the carbon and share it with one of the extra electrons on one of the oxygens, we can
form a second bond. We now have a double bond.
5.
Take the last extra electron on the carbon and share it with the extra electron on one of the last
oxygen, we can form a second double bond. We now have 2 double bonds. Each double bond
counts as 4 electrons. All of our atoms now have 8 valence electrons.
6.
Rewrite the lewis structure of the molecule to make it look neat.
Advanced Covalent Bonding: Draw the lewis structures of the following covalent compounds.
7.
1 carbon atom, 2 oxygen atoms and unlimited hydrogen atoms
8.
1 sulfur atom, 1 nitrogen atom, 2 oxygen atoms, and 1 hydrogen atom
9.
1 Nitrogen atom, 1 hydrogen, and 1 carbon atom
10.
2 Carbon atoms and 2 hydrogen atoms
11.
Hydrogen, Oxygen, and Nitrogen
12.
2 Nitrogens
How to write the chemical formula of a covalent
compound(Problems 13-17)
Example: Write the chemical formula of the compound made from
Nitrogen and Bromine.
1. Draw the lewis structure of the compound that a Nitrogen atom
and bromine atoms make.
Nonmetal
C
Nonmetal
F
Compound
H
O
H2O
C
O
CO2
CF4
2.
Write the atomic symbols of the two elements. The central atom usually goes first.
3.
Since there are 3 bromine atoms in one molecule of this compound, add a “3” subscript after the
Br.
Chemical formulae of covalent compounds: write the chemical formulae of the following covalent
compounds
13.
Phosphorus and chlorine
Answer______________
14.
1 sulfur atom, 1 nitrogen atom, 2 oxygen atoms, and 1 hydrogen atom
Answer______________
15.
Oxygen and fluorine
Answer______________
16.
1 Carbon and 4 Hydrogens
Answer______________
17.
2 Nitrogens
Answer______________
How to name covalent compounds(Problems 18-22)
Example: Name the compound made from nitrogen and bromine.
1. Draw the lewis structure of the compound that nitrogen and bromine make.
2.
Write the chemical formula of the compound that they make.
3.
The first part of the name is just the central atom.
4.
The second part of the name is the second element with the “ide” suffix.
5.
Add in the latin prefix to denote the number of atoms.
Number
2
3
4
5
6
7
8
9
10
Naming covalent compounds: name the following covalent compounds
18.
1 carbon and 2 oxygens
Answer______________
19.
Hydrogen and Chlorine
Answer______________
20.
Oxygen and fluorine
Answer______________
21.
2 carbon atoms and 2 hydrogen atoms
Answer______________
22.
2 carbon atoms and 6 chlorine atoms
Answer______________
Prefix
Bi
Tri
Tetra
Penta
Hexa
Septa
Octa
Nona
Deca