Monday,September 28th 2009.

Today we started talking about quantum numbers and since the beginning Mr. Ariel said that it would be confusing.
In a way they are what tells you where the electrons of a specific atom could be located.
Now there are 4 types of quantum numbers the first would be:
Principal (n):
What this one basically defines the energy levels it has and n=1,2,3, ... up to infinity, but it does HAVE to be a whole number. The bigger n the more energy it has and the farther away form the nucleus it is.
The next quantum number would be:
Angular momentum (l):
What this one does is basically give you the shape of the orbitals, it tells you what part of the energy level the electron is located in.
l=0,...,n-1
And what each number means is which orbital it has... Thinking back to last year they told us about the s, p, d, f orbitals and that's what the numbers stand for.
0=s which is just a sphere.
1=p it's often called a dumbbell and always comes in groups of 3.
2=d it's like 2 dumbbells put together.
3=f is more complex it's like 2 d orbitals put together.
And so on each orbital has a different shape.
YOU CAN HAVE MORE THAN 1 SUB-ORBITAL
an example would be that:
if n=5
l=0,1,2,3,4 and it would have the possibility of having all s,p,d,f orbitals, but it's not always necessarily using them all.
Next is the:
Magnetic number(ml):
This one determines the orientation of the sub-orbits and how many orbitals in a set. (the way it is turned and seen, and how many possible views it has).
ml=-l, 0, +l (it's an L not a one!)
so if l=0 then ml=0 and you'll only have one view, because no matter what way the spherical orbital is turned it will always look the same.
the next one is:
Spin number (ms):
It tells you the direction the electron is spinning.
it can only be +1/2 or -1/2.
It is like the elctronic configuration and the arrows, you always start with the positive (up arrow) and then put in the negative (down arrow).
It will always be 1/2 because it's the way it is, it will NOT change.
The example he showed us was of H (hydrogen), its quantum numbers would be:
n=1
l=0
ml=0
ms=+1/2

If you still had doubts he left two links of two videos on facebook which explain it and might help you grasp it better.
The homework for Friday was the quantum numbers for the following elements Berillium, Boron, Carbon, Nitrogen and Oxygen.

Victoria Bracamontes

Monday, september 21st, 2009

Today we started with the Unit 2.

This unit beggins with a theme that we already saw at the end of the last unit:

¨The atom¨.

Then the next theme in this unit is the ¨Periodic table¨ (OMG! Too much elements to memorize!).

The last theme is ¨Quantum numbers¨ (My head hurts!).

Anyway, back to ¨The atom¨.

The teacher started asking about the atomic model and the light spectrum, the last themes we saw.

After that he spoke a

bout the Light.

The light can be a wave or particles. Better said, it has particles but travels in waves.

The light particles are called Photons.

Then we started with

the waves properties and types.

Crest: Is the highest point in the wave.

Wave length: Is the distance between 2 crests.

Amplitude: Is the distance between a crest and the lowest point call

ed trough.

Electromagnetic Spectrum

Radio waves: Biggest waves. Like TV., AM or FM. 3Km. To 3cm.

Microwaves: From 30cm. To 0.3cm.

Infrared: About 3 micrometers. 1000 micrometers is 1 milimeter. Infrared is familiared with heat.

Visible light: 1 micrometer to 0.4 micrometers.

Ultraviolet: 0.3 micrometers to 4 nanometers.

X-rays: From 3 nanometers to 0.3 nanometers. Can go through almost everything.

Gamma rays: Smaller than 0.3 nanometers. They go through everything. They´re radioactive and cause you harm.

Well...that was the class. And for everyone that was there: The famous and so slippery name in english of ¨valle¨ is trough. :)♥

Erin Alice Gil

Friday, september 4th, 2009

Class started and the classroom was unusually empty, then as Mr. Ariel took attendance people started arriving. Then he started class and as he was warming up to the good stuff the remaining people arrived interrupting his explanation or introduction to the subject of that day which was Atomic Theories.
He started with a little diagram to explain how Aristotle thought that all matter consisted of four elements: Earth, Air, Water, and Fire. and these had 4 qualities: Dryness, wetness, coldness, and hotness.
Everyone believed that until Democritus improved his idea. Democritus believed atoms were indivisible (which was right), and he thought each different thing was made of different substances, not just the four elements. He foreshadowed that there were more elements and that they were indivisible. Then he split us up in groups by choosing 7 "team captains" and having them choose one by one their teams, then switching the captains to a team they didn't make. to explain the rest of the atomin theories.
First came Dalton's model. He said that elements have/composed of tiny indivisible particles called atoms. Also, that the atoms of the same element are identical in size, mass, and chemical properties, and they differ from atoms of different elements. Another thing he said was that all chemical reactions are changes in the proportions of atoms. (Which were all correct thoughts.)
Then in 1897 the Atom was observed for the first time in England. And with came the Electron and Thomson's model He discovered Electrodes: anodes are negative and catons are positive. He realized that electrons move very fast and have negative charges. Which is of 1.602x10^-10.
Radioactivity is a phenomenon where atoms decompose spontaneously. It was discovered accidentally by Henry Bequetel in 1892. Radioactive elements are polanium and radium. The different types of radiation are:
Alpha: Lowest penetrability
Beta:Moderate penetrability
Gamma: High Penetrability
Next was Rutherford's modela nd the Nucleus. Rutherford's theory was that protons and electrons were evenly dispersed. He made an experiment where they shot alpha particles througha thin sheet of gol foil. If he had been correct the particle should've gone straight thorugh unhindered, but since he was mistaken some defleted as they passed through and others bounced back. With that he came up with another atomic model:

In his model protons would be concentrated in a small space and the electrons would be orbiting the empty space around them, and the area where the protons where was called the neutron His model is often called the planetary model becaus of its resemblance to the planets orbiting the sun. The diameter of a typical atom is about 10,000 times greater than the diameter of a typical nucleus. So if the atom was the size of a football field the nucleus would only be the size of a grape.
Then came Bohr's Model. WHich was a proposed quantized shell model og the atom to explain how electrons can have stable orbits around the nucleus: The Quantum Model. It's principles are:
-An atom is composed by a very small nucleus which is a positive charge (Just like Rutherford's model)
-The electrons of an atom can only exist in "special" energetic shells or orbits around the nucleus and can have the names of 1. 2. 3 or K, L, M etc.
-The electrons have definite and characteristic energy according to the shell. K orbit has the lowest radio and energy because it is closest to the nucleus.
-Atoms have two energetic states: Ground state(Stable) and Excited state(too much energy).
When they are in the escited state they need to jump to the next orbit but by doing that they get tired and lose energy so they have to bounce back to their original orbit this movement is called a transition, and each jump has a characteristic light(emission spectrum) it gives out.


Then came Sommerfeld's model which was just Arnold Sommefeld's improved quantum model Saying that there was the same amount of protons and electrons, and that the shells could be circular or elliptical.
Then came the Modern Model which was established by Schrodinger and Dirac. It is a complex mathematical model. It is the result of integration of different knowledge. It sattes that electrons are distributed around the nucleus in probability regions called atomic orbitals. It is also called Quantum mechanical model. It was proposed because:
a. Albert Einstein explained the Photoelectric effect.
b. Louis De Broglie proposed that matter has a particle/wave duability.
c Werner Heinsberg proposed the Uncertainty Principle

And that was basically the whole class, just taking notes on the presentations. He did sat we should watch a video titled : "What the 'bleep' do we know?" to help understand it better.

Victoria Bracamontes

Monday, August 31st, 2009

First I want to say that teacher is kind of frustrating I don't know, is just my opinion, and I really needed to say it, I know students are too, but oh just anyways, that is just my opinion. And to say I was really paying attention
Let's talk about the real journal the thing that really matters, during last class we were talking about matter and its properties, It divides into General Properties and Specific properties.\

Matter Properties.

General Properties: They are common to all kinds of matter.

Volume: Space that matter occupies.
Mass: Ammount of matter contained in a body.
Inertia:Opposition that a body presents to change its movement or its static state.
Weight: Measure of force of attraction between objects due to gravity
Elasticity: When bodies can be temporarily deformed by an external force.
Impenetrability:Two bodies can't occupy tha same space at the same time.
Porosity: All bodies present spaces between particles.
Divisbility: All bodies can be decomposed by mechanical or energetical means.

Specific Properties: Helps to identify a substance from another one.
It can be divided into Physical and Chemical.

Physical property: It can be measured and observed without changing its composition or identy of a substance.

• Changes can be reversible.
• Nothing is used up.
• Nothing is formed.

Chemical properties: Refers to a characteristic that matter exhibits as it undergoes a change in its composition.

• One or more substances are consumed.
• One or more sibstances are formed.
• Energy is absorbed or released.

EXAMPLES.
Physical: State of matter, Odor, density, temprerature, melting point, boiling point.
Chemical: Reactivity, acidity, vapor pressure, solubility, thermal stability, oxidand strength, reductant strength.

Properties can also be classfied on the basics of whether they depend on how much of matter is present.

Extensive properties: Are dependamnt upon the ammount of substance present.
Example: Mass, Volume.

Intensive properties: Are independant of the ammount of matter.
Example: Color.

Okay, my opinion about this, classes are starting to be boring, I mean, I understood it, but if we always do the same it kinda make me feel sleepy or anything, anyways, this topic I think I understood it very well.

Energy.
It is the capacity to do a work.

Energy can be presented into two states:

Kinetic or movement energy: Energy of a body because of its movement.
Example: Waterfalls.
Potential or stored energy: Energy of a body because pf its position.
Example: Water stored in a dam.


Conservation Laws.
Matter conservation Law: Mass is neither created or destroyed, just transformed. -Antoine Lavoisier.
Energy conservation Law: Energy is neither created or destroyed, just transformed. -Robert Mayer.
Mass-Energy conservation Law: The ammount of mass-energy that is present in the universe is constant. -Albert Einstein.

Kabick Tam