Bonding Construction Activity
Ionic Bonding
Atoms can achieve a noble gas electron configuration by losing or gaining electrons to
form ions. Metals lose electrons to form positive ions and non-metals gain electrons to
form negative ions.
Sodium can attain the stable electron configuration of neon by losing one electron
Na (1s22s22p63s1)
Na+ (1s22s22p6 – Neon’s stable configuration) + 1e-
With ten electrons and eleven protons the ion formed has a positive charge (Na+1).
Fluorine is one electron short of the neon electron configuration. If it obtains one
electron (from sodium) it can achieve a full outer shell of eight electrons.
F (1s22s22p5) + 1e-
F- (1s22s22p6 – Neon’s stable configuration)
The species formed has ten electrons and nine protons; it is a negatively charged fluoride
ion (F-1).
Na · +
xx
x
x Fx
xx
+
xx
x
x F x
xx
-
·
Na
Properties of Ionic Compounds
1. Crystalline solids
2. High melting and boiling points
3. Soluble in water
4. Conduct electricity when molten or dissolved in water
Covalent Bonding
Covalent bonds are formed by the sharing of electrons between non-metal atoms. The
two atoms have to approach sufficiently close to each other for their atomic orbitals to
overlap.
Dot-and cross Diagrams
Dot-and cross diagrams are simplified versions of the diagram for the chlorine molecule
on the left below, showing only the outer shell electrons
Multiple Covalent Bonds
Multiple covalent bonds may involve the sharing of two or even three pairs of electrons
between atoms.
or N
N
Properties of Covalent Compounds
1. Usually soft and brittle
2. Low melting and boiling points
3. Insoluble in water
4. Do not conduct electricity when solid or molten
Prelab Questions:
1.
Ionic bonds are formed between ___________ and ______________.
2. When an ionic bond forms, electrons are _______________ between atoms.
3. Cations and anions try to gain or lose electrons to reach a _____________ electron
arrangement in their valence shells just like _____________ gases.
4. Covalent bonds are formed between ___________ and _____________.
5. When covalent bonds form, electrons are ______________ between atoms.
6. How are ionic and covalent compounds different in their properties? (discuss 4)
7. Complete the table:
Ionic Compound Construction
Instructions:
Read through the instructions before you begin…
1. Using nonpermanent markers, color the valence electrons on each element card
that you will be using to construct ionic formulas. Color metal valence
electrons red. Color nonmetal valence electrons blue.
2. On your desktop, construct ionic compounds using element cards. Remember,
metals will lose electrons to nonmetals during a chemical reaction.
3. Also remember that metals are trying to reach a stable octet by losing their
valence shell, nonmetals want to gain enough electrons in their valence shell to
reach a stable octet of electrons (like a noble gas). Your teacher will
demonstrate how to build the model for magnesium + oxygen.
Example: Magnesium + oxygen
4. Draw the formula structure on your answer sheet. Use arrows to show the
electron transfer from the metal to the nonmetal.
5. Write the resulting formula MgO
6. Name the compound Magnesium oxide
Ionic Compound Construction Site
1. Potassium + oxygen
Teacher initials for model ____________________
Ionic formula structure w/arrows:
Formula ___________
Name __________________________________________
2. Aluminum + chlorine
Teacher initials for model ____________________
Ionic formula structure w/arrows:
Formula ___________
Name __________________________________________
3. Magnesium + sulfur
Teacher initials for model ____________________
Ionic formula structure w/arrows:
Formula ___________
Name _________________________________________
4. Sodium + phosphorus
Teacher initials for model ____________________
Ionic formula structure w/arrows:
Formula ___________
Name __________________________________________
Build your own ionic compound (remember metal-nonmetal)
5. ____________________ + _____________________
Teacher initials for model ____________________
Ionic formula structure w/arrows:
Formula ___________
Name __________________________________________
Covalent Compound Construction
Instructions:
1. Color the valence electrons on each card you will be using to construct your
covalent compounds. Color the first atom in the covalent formula red; color
the second atom blue.
2. Construct the molecular compound pairing up valence electrons.
3. Draw the formula structure on your answer sheet. Show the sharing of
electrons and stable octets around atoms by drawing circles around the
element s and their valence electrons.
4. Your teacher will demonstrate how to build the molecular compound CH4
Example: CH4
Covalent Compound Construction Site
1. NI3
Teacher initials for covalent model ____________________
Molecular structure w/ circles:
2. SiO2
Teacher initials for covalent model ____________________
Molecular structure w/ circles:
3. PCl3
Teacher initials for covalent model ____________________
Molecular structure w/ circles:
4. CI4
Teacher initials for covalent model ____________________
Molecular structure w/ circles:
Build your own covalent compound
5. (remember, nonmetal-nonmetal)
Teacher initials for covalent model ____________________
Molecular structure w/ circles:
Molecular Formula _______________
Conclusion:
Discuss three differences between ionic compounds and covalent compounds.
One difference between ionic and covalent compounds is______________________
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