Carbon has four electrons in outer shell and hydrogen has one electron in its outer shell. Carbon must share four more electrons to have eight electrons in its outer shell (to fill the outer shell) and hydrogen needs to have only one more electron to have two electrons in its outer shell (to fill the outer shell). Therefore it will take a total of four hydrogen atoms to balance the valence shells of the carbon and four hydrogen atoms. Each line projecting from carbon above represents a single covalent bond. Think of each line (covalent bond) as containing two electrons, one from the carbon and one from the hydrogen atom. Since these are shared and not transferred each hydrogen has two electrons and the carbon has a total of eight.
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2. The correct answer is false. Molecules with covalent bonding
do not have a charge because they share their electrons. Ions
have a charge and they transfer their electrons.
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3. Hydrogen will always have only one covalent bond. Whenever
you see hydrogen in an organic molecules it will always have a single line
projecting from it. See below.
H
|
H- as in
H-C-H
or H-H
|
H
Note: Because hydrogen has only one bond it will always be located
on the outside of an organic molecule.
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4. Oxygen will always have two covalent bonds.
H
|
-O- as in
H-O-C-H or
O=O
|
H
Note: Each hydrogen has only one bond, carbon four bonds,
and oxygen two bonds.
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| Element | Number of valence electrons | Number of covalent bonds |
| Carbon | 4 | 4 |
| Hydrogen | 1 | 1 |
| Oxygen | 6 | 2 |
| Nitrogen | 5 | 3 |
| Phosphorus | 3 | 5 |
| Sulfur | 6 | 2 |
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6. The correct answer is 14 hydrogen atoms.
H H H H H H
| | | | |
|
H-C-C-C-C-C-C-H or CH3CH2CH2CH2CH2CH3
| | | | |
|
H H H H H H
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7. The correct answer is 8 hydrogen atoms.
H H H
| | |
H-C-C-C-O-H
| | |
H H H
Note: Each carbon has four bonds, hydrogen one and oxygen two.
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8. The group attached to the carbon skeleton is an
-OH group. This is called an alcohol group.
If an -OH (note the bond between the O and the H is not shown) is attached
to a carbon that has only hydrogen attached, it is called an alcohol.
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H H
| |
9. Yes!! H-C-O-C-H
| |
H H
Note: Same formula - C2H6 O
and each carbon has four bonds, hydrogen one bond and oxygen two bonds,
both of these are functional molecules with covalent bonding.
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10. Both of these are correct. They both have the same molecular
formula but different structural formula. Such molecules are called
isomers. Write out the answer for behavioral objective 21.
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11. The answer is eleven single covalent bonds and one
double covalent bond.
(singles are four around the first
carbon, one on the second, one on the third, four around
the fourth and one
out of the oxygen)
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H H H
H H H
| | |
| | |
12. H-C-C=C-O-H
or
H-C=C-C-O-H or
|
|
H
H
H H H
| | |
H-C=C-O-C-H
etc.
|
H
Note: These all consist of three carbon atoms, six hydrogen atoms, one
oxygen atom and each carbon has four bonds (some single and some double),
each hydrogen one bond, and each oxygen two bonds.
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