WebElements Image

A simple model of a nitrogen atom. Inside the silver ball in the center (nucleus), there are 7 protons and 7 neutrons. The 7 electrons orbiting the nucleus are found in two electron shells since the inside shell can hold only two electrons.

Physical Properties of Matter

• All matter has mass. Mass is the amount of matter in an object.
• Weight and mass are not the same thing. Weight is the effect of gravity on an object. (Example: A brick has a certain mass. That brick will have a certain weight on earth, a different weight on the moon, and a third weight in outer space. The mass is the same everywhere, but the weight changes).
• All matter has volume. Volume is the amount of space an object takes up.

• WebElements

• Table giving the biological role(s) of the various elements.

• WebElements Images

  Two different representations of the abundance of different elements in the human body. Both are logarithmic representations since, in reality, oxygen, carbon, and hydrogen are so much more abundant than anything else. Click on a picture to see it enlarged. Click here to see the full page at WebElements.

Links:

• Chemicool Periodic Table
• CHEMystery: An Interactive Guide to Chemistry
• General Chemistry - U. Florida
• MathMol Hypermedia Textbook
• MathMol LibraryAnimated Tutorial: Chemical Bonds (requires Shockwave)
• IUPAC Nomenclature of Organic Chemistry
• Science (Chemistry) Is Fun - Bassam Z. Shakhashiri, U. Wisconsin
• Chemistry - Biology Project
• Acids and Bases - Biology Project
• Clinical Correlates of pH Levels - Biology Project