Tuesday, November 6, 2007

On Monday, we learned about the chemistry of life. Although this is an AP Biology class, we study chemistry because it is the foundation of Biology.

As many of us have learned across the hall in the Chemistry rooms, everything is made of matter. Matter is made of atoms that are made up of electrons, protons and neutrons.
In this biology course, we only need to worry about ten elements on the periodic table: hydrogen, magnesium, potasium, sodium, calcium, carbon, nitrogen, oxygen, phosphorus and sulfate. Hydrogen, carbon, nitrogen, and oxygen are the key elements that our human body is made up of. Phosphorus is in DNA and ATP.

We also went on to learn about the bonding properties and the effect of electrons. Electrons determine the chemical behavior of an atom, depending on the the number of electrons in an atom's outermost shell. The valence shell is nonactive.
Atoms with many electrons in its valence shell have high electronegativity and tend to want to "steal" electrons from other atoms while atoms with fewer electrons have low electronegativity in their valence shell and tend to want to "donate" to other atoms. These atoms with fewer electrons donate bececause they cannot hold that many electrons themselves. These tendencies drive chemical reactions and create bonds. A chief principle that we learned Monday was that when we think of weak bonds, hydrogen bonds should be the very first thing we think of while when strong bonds are mentioned, covalent bonds should be thought of immediately. Covalent bonds are strong because two atoms share a pair of electons and both atoms hold onto the electrons, making them very stable. This forms molecules. The more pairs of electrons shared, the stronger the bond. More is better!

PAGEMASTER will be our next sherpaaaaa!

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