fig. 2-2. atoms have nuclei and electrons. the nuclei contains positive charges and the electrons...
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![Page 1: Fig. 2-2. Atoms have nuclei and electrons. The nuclei contains positive charges and the electrons are negatively charged](https://reader035.vdocument.in/reader035/viewer/2022062320/56649d7a5503460f94a5de80/html5/thumbnails/1.jpg)
Fig. 2-2. Atoms have nuclei and electrons. The nuclei contains positive charges and the
electrons are negatively charged.
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Any atom has an equal number of positive charges in its nucleus and negative charges
in its electrons.
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The electrons exist at particular levels.
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Molecules
• Molecules are formed when atoms are connected to one another.
• These connections are called “bonds” and can be thought of as an attractive force that holds the parts of the molecule together.
• We will talk about ionic bonds, covalent bonds, and hydrogen bonds.
![Page 5: Fig. 2-2. Atoms have nuclei and electrons. The nuclei contains positive charges and the electrons are negatively charged](https://reader035.vdocument.in/reader035/viewer/2022062320/56649d7a5503460f94a5de80/html5/thumbnails/5.jpg)
Ions are formed when electrons are transferred.
The charged ions are then
attracted to one another due to their opposite charges. We
see this in Fig. 2-3
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Now go to your notes for the explanation of how covalent bonds
are formed.
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Fig. 2-4. Here are some examples of
molecules held together by covalent
bonds.
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Now we need to ask the question “Where are these shared electrons most likely to be found?” There are
two answers:
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Now we need to ask the question “Where are these shared electrons most likely to be found?” There are
two answers:
• The electrons may be uniformly distributed throughout the molecule.
![Page 10: Fig. 2-2. Atoms have nuclei and electrons. The nuclei contains positive charges and the electrons are negatively charged](https://reader035.vdocument.in/reader035/viewer/2022062320/56649d7a5503460f94a5de80/html5/thumbnails/10.jpg)
Now we need to ask the question “Where are these shared electrons most likely to be found?” There are
two answers:
• The electrons may be uniformly distributed throughout the molecule.
• The electrons may be more likely found at one end or the other of the molecule.
![Page 11: Fig. 2-2. Atoms have nuclei and electrons. The nuclei contains positive charges and the electrons are negatively charged](https://reader035.vdocument.in/reader035/viewer/2022062320/56649d7a5503460f94a5de80/html5/thumbnails/11.jpg)
Now you need to go to your notes to see the consequences of these
two different answers.
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![Page 13: Fig. 2-2. Atoms have nuclei and electrons. The nuclei contains positive charges and the electrons are negatively charged](https://reader035.vdocument.in/reader035/viewer/2022062320/56649d7a5503460f94a5de80/html5/thumbnails/13.jpg)
Fig. 2-5 shows the most famous of the polar compounds, water.
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• Since polar compounds have unlike partial charges, they will attract one another at their unlike charges.
• Remember that an attraction between molecules is a bond?
• This attraction between polar compounds is another type of bond. . . .
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These bonds are
called hydrogen bonds and are shown in Fig. 2-6.
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Individual hydrogen bonds are very weak, but there are SO MANY OF THEM!!!!!
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Here is a brief review of the three types of bonds:
• Covalent: formed by the sharing of electrons. These are the strongest bonds.
• Ionic: formed by the attractions between charged ions resulting from the transfer of electrons. These are intermediate in their strength.
• Hydrogen: attractions between partial charges found in polar covalent compounds.