Week Two Assignments - Periodic Tables and Atomic Structures

Carbon:
The symbol for carbon is C, and its atomic number is 6; it is a nonmetal
Carbon was known to man from the ancient world, and has been around before recorded history. It exists in all known life forms, and forms the chemical basis of all life on Earth. Because of its affinity for bonding with other small atoms, it forms almost ten million different compounds – the large majority of all known compounds. Carbon is the 4th most abundant element in the universe, and is the 2nd most abundant element in the human body.
Two of the most commonly known allotropes (a variant of molecular structure of an atom with new physical properties) of carbon are diamonds and graphite. The following comparisons are from Wikipedia.com, and they show the differences between the two (essentially, they are polar opposites – and yet, they are both carbon).

Synthetic diamond nanorods are the hardest materials known.
Graphite is one of the softest materials known.
Diamond is the ultimate abrasive.
Graphite is a very good lubricant.
Diamond is an excellent electrical insulator.
Graphite is a conductor of electricity.
Diamond is the best known thermal conductor
Some forms of graphite are used for thermal insulation (i.e. firebreaks and heatshields)
Diamond is highly transparent.
Graphite is opaque.
Diamond crystallizes in the cubic system.
Graphite crystallizes in the hexagonal system.
Amorphous carbon is completely isotropic.
Carbon nanotubes are among the most anisotropic materials ever produced.

Ozone discussion:
....to follow. :)

Review – Elements, Compounds & Mixtures:
Ok, I have to confess, I reviewed this site mainly because the other two were pretty dry and this one had pretty pretty graphics….tee hee. For myself, I appreciate pictures that illustrate a concept which essentially I find difficult – the more variants I have on an explanation will usually help me to understand a bit better; I also find bullet points which explain an idea or concept to be easier to follow and understand – again, backing it up with an illustration being most helpful.
I do suppose that the other two websites ultimately provide more information; but when I am faced with a somewhat overwhelming concept which I am going to have to get my head around, then the simpler approach is definitely the way to go for me. J