Atomic Structure Chemistry Hot List

Chemistry Hot List -- Atomic Structure

"Understanding means seeing that the same thing said different ways IS the same thing." --- Ludwig Wittgenstein

Atomic Structure Timeline:

http://www.watertown.k12.wi.us/HS/Staff/Buescher/atomtime.asp

Atomic Structure: Explores first, why atoms naturally arrange themselves to form a structure. Then we will look at some common structures, and ask why diamonds are forever, but salt is of the earth - all of which will help us understand the different kinds of bonding between atoms.

http://www.ill.fr/dif/3D-crystals/intro.html -- can copy paste pictures:

Cool site with animated graphics and building of atoms to create the periodic table. http://web.jjay.cuny.edu/~acarpi/NSC/3-atoms.htm

This is very basic but cute…

ATOMS AND ATOMIC STRUCTURE: Chem4Kids.com
Learn about atomic structure, orbitals, bonding, compounds and isotopes.

Here’s a site with this concept map: http://hyperphysics.phy-astr.gsu.edu/hbase/quantum/atomstructcon.html

avogadro.jpg (12825 bytes)

Avogadro's Number

The name "Avogadro's Number" is just an honorary name attached to the calculated value of the number of atoms, molecules, etc. in a gram mole of any chemical substance. http://gemini.tntech.edu/~tfurtsch/scihist/avogadro.htm

And on to Mole and Molar Mass ---

http://ask.yahoo.com/ask/19991123.html

Activity for comparison: http://chem.lapeer.org/Chem1Docs/MolExercise.html

Connection to mass of protons and neutrons http://www.wikipedia.org/wiki/Avogadro's_number

A Carbon-12 atom consists of 6 protons and 6 neutrons (which have approximately the same mass) and 6 electrons (whose mass is negligible in comparison). One could therefore think that N_A is the number of protons or neutrons that have a mass of 1 gram. While this is approximately correct, the mass of a free proton is 1.00727 amu, so a mole of protons would actually have a mass of 1.00727 g. Similarly, a mole of neutrons has a mass of 1.00866 g. Clearly, 6 moles of protons combined with six moles of neutrons would have a mass greater than 12 g. So, you might ask how one mole of Carbon-12 atoms, which should consist of 6 moles each of protons, neutrons, and electrons could possibly have a mass of only 12 g? What happened to the excess mass? The answer is related to the equivalence of matter and energy discovered by Albert Einstein as part of the theory of special relativity. When an atom is formed, the protons and neutrons in the nucleus are bound together by the strong nuclear force. This binding results in the formation of a low energy state and is accompanied by a large release of energy. Since energy is equivalent to mass, the released energy corresponds to a loss in the mass of the nucleus relative to that of the separated protons and neutrons. Thus, protons and neutrons in the nucleus have masses that are less (about 0.7 percent less) than free protons and neutrons. The precise amount of mass loss is related to the binding energy of the nucleus and varies depending on the type of atom.

One may therefore say that N_A is approximately the number of nuclear neutrons or protons that have a mass of 1 gram. This is approximate because the precise mass of a nuclear proton or neutron depends on the composition of the nucleus.