Heaviest Element named

The heaviest element yet known is now officially named "Copernicium," after the astronomer Nicolaus Copernicus. Copernicium has the atomic number 112 — this number denotes the number of protons in the nucleus of an atom. It is 277 times heavier than hydrogen, making it the heaviest element officially recognized by international union for chemistry IUPAC.

Test #2 Chapter 4, 5, and 6

This week on Monday and Tuesday we began Chapter 6. Our next test, Test #2, will be on March 3 and 4. We have covered Atomic Structure, Chemical Periodicity, and Chemical Reactions.

Don't forget to bring a Scantron.

Effective Nuclear Charge

The effective nuclear charge, is the net positive charge experienced by an electron in a multi-electron atom. The term "effective" is used because the shielding effect of negative electrons prevents higher orbital electrons from experiencing the full nuclear charge. It is possible to determine the strength of the nuclear charge by looking at the oxidation number of the atom.

In an atom with many electrons the outer electrons are simultaneously attracted to the positive nucleus and repelled by the negatively charged electrons. The effective nuclear charge on such an electron is given by the following equation:

Z_eff = Z − S

where

Z is the number of protons in the nucleus (atomic number)

S is the average number of electrons between the nucleus and the electron in question (the number of nonvalence electrons).

http://en.wikipedia.org/wiki/Effective_nuclear_charge

Atomic Structure

We've been talking about quantum chemistry including the nature of light and radiation. This is so we can look at electrons a little more closely and understand their behavior as particles with wave-like character. A direct result of this wave-like character is that electrons exist in regions of space that are called orbitals. Understanding orbitals helps us interpret the chemistry that we have seen and allows us to predict various properties of atoms, ions and molecules.


This video may help http://www.youtube.com/watch?v=M2wDLePcCQU.

Atomic Structure

Last week we began our study of Atomic Structure. We covered the discovery of the electron, proton, and neutron; the nucleotide symbol, isotopes, and average atomic mass. Then we began our study of Electromagnetic Radiation.

Stoichionetry Hint!!!

For any stoichiometry problems, there are a logical set of steps to follow:

1. Balance the equation.

2. Convert the quantity you know into mols.

3. Convert mols of what you know to "mols of interest" using the coefficients (ratios) in the balanced equation.

4. Convert "mols of interest" into a useful number. That useful number might be a mass or a volume or a number of other things, it all depends upon the problem.

Test #1

Don't forget to bring a Scantron to the test.

Notice!!! New Location for General Chemistry (CHEM 1212K) Blog

Please note, a new address for General Chemistry (CHEM 1212K) is located at: http://ghcchem2.blogspot.com/.

The CHEM 1211K site will remain at the current location.

Chem 1211K and 1212K Test #1

Both the Chem 1211K and 1212K tests will have 20 multiple-choice questions.

I will give you a periodic table.

You may use one 3" x 5" index card with anything you would like written by hand.

Good luck. let's get off to a great start. Study, study, study!!!!!