Chemistry of Life
MatterOccupies space and has mass
MassHow much matter an object has
WeightForce of gravity pulling on an object
http://www.rgvchallengerlearningcenter.com/Space%20walk1.jpg
Elements and Atoms
Elements•Cannot be broken down into simpler kinds of matter•More than 100 exist•Fewer than 30 are important to life
Atoms and Molecules
Atom:The smallest unit of an element having all the characteristics of that element
•Electrons: negative, orbit around the nucleus, almost no mass•Protons: positive, in nucleus, mass of 1•Neutrons: neutral, in nucleus, mass of 1
http://education.jlab.org/qa/atom_model_02.gif
Atoms and Molecules
MoleculesThe smallest particle of a substance that retains the properties of the substance; composed of two or more atoms
http://www.sdsc.edu/GatherScatter/gsmar94/Images/molecule.gif
What do you remember from Junior High Science?
Atomic Number:Number of protons
Mass Number:Protons + Neutrons
Ion:+ or - charged atom
Isotope:Atoms of the same element with different numbers of neutrons (and therefore different masses)
http://serc.carleton.edu/images/introgeo/quantskills/CFourteen.gif
Bohr Model of the Atom(This model is out-of-date, but still useful for basic chemistry…)
http://js082.k12.sd.us/My_Classes/Physical_Science/atoms/atom-bohr.gif
What to remember:•Up to
•2 e- in the first shell•8 e- in the next two shells
This is what the “new” model looks like:
Ionic Bonds
When one atom donates e- to another atom.•Leads to + and - charged atoms•Attracted to each other•Overall, the molecule is neutral
Covalent Bonds
CHHHH
When atoms SHARE e- to form a neutral molecule
Methane
So how do scientists think the UNIVERSE began?
http://rhysy.plexersoft.com/Explosion%20test%202e.jpg
The formation of Earth…
•Molten gases and materials cooled•Made of atoms with different weights•Some sank; some floated to surface
http://geology.com/news/images/tungurahua-volcano.jpg
LifeLife formed on the surface from the less dense elements.
http://www.solstation.com/stars/earth2.jpg
HHydrogen OOxygen
NNitrogen CCarbon
Most common biological bonds in nature…
96% of all living matter is composed of:
H, O, N, and C
Stable or Unstable?For molecules composed of H, O, N, and/or C, just count the covalent bonds.
•Correct number? STABLE•Wrong number? UNSTABLE
O=O O=C=O-HSTABLE UNSTABLE