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Author Topic: diamond and ice bonding reflect refract.  (Read 1308 times)
maddog
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« on: June 05, 2007, 06:23:38 AM »

Use the differences in the type of bonding exhibited by these substances to explain the following

1. Diamond is transparent, reflects and refracts light and is non-conducting, but graphite is black, opaque and will conduct electricity. why.

2. Both ice and diamond are colourless and transparent crystals, but diamond is extremely hard and has a very high melting point, while ice is much less hard and melts at only 100oC. why.


i dont know the answers to these questions. can someone  please answer them. pleas3e i am beeggging
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ChemHelper
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« Reply #1 on: June 06, 2007, 12:51:12 AM »

Hello maddog,

I hope this explanation works for you.

Diamond vs Graphite:

The carbon atom  can make 4 chemical bonds (shared-electron-links) to
its neighbors.
In a diamond, each atom links to 4 different neighbors, and every electron
is bound (confined) within its own link.
So there are no mobile electrons, and diamond is a dielectric not a
conductor, and  it is clear, not absorbing.

In graphite, each atom links to only 3 neighbors, making a flat sheet, and
each has one electron left over.
All of these leftover electrons are shared in common by the whole sheet.
The electrons of this pool are mobile, so graphite conducts
electricity and absorbs light.
It is worth mentioning that there are not many elements which have a choice of whether or not to be conductive.

If you still have questions about what I have said here then please come back and we can continue this discussion.

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