Questions?
Contact Becki Williams
bwilliams@dcccd.edu
Chemistry Concepts
Want to learn the names and symbols of the elements? The attached file, Memorizing Elements shows you how to organize the symbols so that it's a more manageable task.
The model of the atom has changed since the particle was suggested by John Dalton in 1808. Check out how the model has been modified in the History of Atomic Model. Notice that the Bohr Model was replaced in 1927.
The image on the left correctly depicts the quantum mechanical model of the atom. Notice that there are no ORBITS in this model!
Molecular Polarity can be difficult to predict. First draw a correct Lewis Structure. Then classify the central atom, using the AXE classification scheme, and determine the electron pair and molecular geometry. Draw a rough sketch of the molecular geometry. Then use the electronegativity table to label each bond that is polar. Now you're ready to predict molecular geometry. WHEW! Use the visual organizer, Polar Molecule? to correctly
predict molecular polarity.