PBS Learning Media Simulation: Tutorial Covalent Bonding
http://www.pbslearningmedia.org/resource/lsps07.sci.phys.matter.covalentbond/
covalent-bonding/
This interactive activity from ChemThink describes covalent bonding—a type of
chemical bond that involves the sharing of electrons.
 Investigate the attractive and repulsive forces that act on atomic particles
and how the sharing of electrons can keep atoms together.
 See how two hydrogen atoms interact with each other to create a covalent
bond.
 Learn about trends in the periodic table and how electrostatic potential
energy determines the bond length.
 Also, learn about naming conventions for covalent compounds.
Follow the instructions closely as you move through this activity! There are some
screens where you have to do something before you can move onto the following
screen. This media asset was adapted from ChemThink.
Student Questions
1. In the two hydrogen atoms simulation, how is the movement of electrons
different when the atoms are close? Explain the electron location using
electric force and Coulomb’s Law. What happens if you try to move the
atoms too close to each other?
2. What is a covalent bond?
3. What type of elements form covalent bonds? Why does hydrogen behave
differently from other elements in its group when it comes to bonding?
4. In the potential energy simulation, why does the potential energy between
the atoms decrease as you move them closer together?
5. In the potential energy simulation, after a certain point, the potential energy
increases if you try to move the atoms any closer. Why does this happen?
6. What determines the bond length of a covalent bond?
7. In terms of stability, why do atoms form covalent bonds?
8. In the formula H-H, what does the line represent?
9. How many pairs of electrons does oxygen share? Depict oxygen bonding
using lines to represent bonds.
10. How many electrons total are shared in a triple bond?
11. Triple bonds are strongest, followed by double bonds and single bonds are
weakest. Explain this trend using electric force and Coulomb’s Law in your
answer.
12. Write the names of the following covalent compounds:
a.
b.
c.
d.
e.
f.
g.
h.
i.
j.
k.
N2O
NO2
N2O4
N2O3
NO
H2O
S2O
SO3
S2O3
SO2
S2Cl2
Answers
1. When you move atoms toward each other, the electrons move around
between the two atoms. The electrons are attracted to the two positive nuclei
between, and, according to Coulomb’s Law, the strength of the force
increases as they atoms get closer to each other, so the electric force draws
them into the middle between the two positive nuclei. When you try to move
the atoms two close, their positive nuclei repel each other.
2. A covalent bond is an electric force of attraction between two atoms that
share outer electrons.
3. Nonmetals form covalent bonds because they are fairly electronegative and
two or more unpaired valence electrons. Hydrogen only has one valence
electron close to the nucleus, so it is more electronegative than other
elements in its group, behaves like a nonmetal and shares electrons with
other atoms to become stable.
4. Each nucleus is attracting the other atom’s electron with increasing strength
so it takes less energy to keep them apart.
5. The protons in each nucleus are repelling each other strongly, it takes more
energy to move the atoms closer together at this point.
6. When the atoms are arranged so that the potential energy is at a minimum,
they have achieved the most stable balance between the attractions and
repulsions.
7. The atoms are more stable when they are bonded because their outer
electron energy levels are full by sharing electrons with another atom.
8. A pair of shared electrons
9. Oxygen shares two pairs of electrons; O=O
10. 6
11. Triple bonds involve 6 electrons whereas double bonds only involve 4
electrons and single bonds 2 electrons. According to Coulomb’s Law, the
greater the magnitude of the charge, the stronger the electric force.
12.
a. N2O dinitrogen oxide
b. NO2 nitrogen dioxide
c. N2O4 dinitrogen tetroxide
d. N2O3 dinitrogen trioxide
e. NO nitrogen monoxide
f. H2O dihydrogen oxide
g. S2O disulfur oxide
h. SO3 sulfur trioxide
i. S2O3 disulfur trioxide
j. SO2 sulfur dioxide
k. S2Cl2 disulfur dichloride