The structure of atoms and periodic trends.

Hello!  I hope everyone had a great weekend.  This week we begin to develop some ideas about what the quantum numbers mean.
For Students:
Here are the answers to last week's quiz:
1.  Which of the following radiation involves less energy, x-rays or microwaves?  microwaves
2.  Place the following types of radiation in order of increasing energy per photon?
fm station < yellow light < x-rays
3.  An electron moves with a velocity of 2.5 x 10^8 cm/s.  What is its wavelength?
.29 nanometers
4.  How many subshells occur in the electron shell with the principal quantum number n=4?
four
5.  State which of the following orbitals cannot exist according to the quantum theory?
2d and 3f orbitals can't exist (n=2 subshell can only have a s or p subshell and n=3 can only have s, p or d subshells)

I hope everyone did well.  We now move on to new material.  To make the quantum theory work, the Austrian physicist Wolfgang Pauli stated in 1925 his exclusion principle: no two electrons in an atom can have the same four quantum numbers.  The result of this is that no more than two electrons can be in the same orbital.  One with an "up" charge and one with a "down" charge.  We will depict this using orbital box diagrams:

For example, when you want to depict the two electrons that make up a helium atom you would start at the bottom level, the 1S level and draw one arrow up and one arrow down inside the box.  That tells us that you have two electons in the 1S orbital, one spinning in the positive direction and one spinning in the negative direction.  Please note that these directions are completely arbitrary, it just helps us understand that there can't be two identical electrons in an atom.  Also it is important to note that s orbitals have one box, p orbitals have 3 boxes and d orbitals have 5 boxes.  How many boxes do you think an f orbital would have??  Seven is right!  The order of increasing energy must be memorized.  This will be on your next quiz.  The order is (starting at the bottom and working our way up): 1S, 2S, 2P, 2S,3P,3D, 4S, 4P, etc.

For Parents:
There have been a few difficulties lately regarding significant figures and scientific notation.  An error in this regard will not make the answer to a problem wrong, but I will have to start taking off a point of two.  If your child needs help in this area I will be available after school as usual and I will be giving out a review sheet to help with this.  If you have any questions let me know.  Thanks and have a great day!