Atomic Models =O

If I tell you when did the first contribution of this complex but interesting model took place, you would be surprised; Well, FYI the first contribution was by Democritus, approximately in 400 BC, he said that matter was composed by small particles called atoms; Then until 1804, when Mr. John Dalton came and added something to the model, that atoms of the same element are identical, that during reactions atoms are just rearranged, and that atoms combines in multiples. The next contributor is Dmitri Mendeleev, in 1869, arranged the elements known to his times in a table that today we know as periodic table of the elements; Next in 1896-9 Henri Becquerel discovered that elements have properties, he experimented with Uranium, Rutherford made an expeiment and achieved the separation of alfa and beta particles from gamma rays. In 1897 J.J. Thompson discovered the elctron after his experimentations. Between 1909 and 1911 Geiger and Rutherford identified a nucleus on the atom, this discovery was aided by the experiment of the gold foil.

In 1913 Robert Milikan experimented and did some research to identify the mass of an electron, in the same year, J.J. Thompson discovered the positively charges particles on the nucleus and discovered the isotopes and H. Mosely  determined the atomic mass of the elements, and also reorganized the periodic table.

In 1919 Mr. Rutherford, proposed the existence of neutrons on the nucleus, as he confirmed protons.

The last significant contribution, was the one by James Chadwick in the 1930's he confirmed the nucleus as the center of the particles.

The following image illustrates the models as the were imgined by each of the scientists.

References

Document about atomic model 

http://www.docstoc.com/docs/24255154/Atomic-Models-_In-chronological-order-of-discovery__

A brief history of Atomic Theory development

http://www.neoam.cc.ok.us/~rjones/Pages/online1014/chemistry/chapter_8/pages/history_of_atom.html

Assignement!!! :O

This Thursday I was assigned to look for an ingredient of some daily producta and investigate about it...
I decided to look on my antipespirant and I just chose one that got my eye...Propylen Glycol!!
It is usually used and cosmetic and personal hygenie products.
After my little research I found that the properties of this ingredient is :
It can be used on the body as part of certain products like shampoos or deodorants...it has an humescent effect on the body...it retains moisture produced by the body (such as fat produced by the hair, or the sweat produced under your arms...:O)...But although it helps sometimes, it may also irritate the skin and produce certain disfunctions with the KIDNEY!!
Well maybe the last part is not exactly related with Chemistry...but here is te part that has to do with it:
It has Carbon, Hydrogen and Oxygen!! Carbon is the element for organic chemistry, the chemistry that is closer to life, EVERYTHING that has life, contains carbon...(:
Its chemical formula is C3H8O2...It is soluble in certain substances, such as water, ethanol and acetone
That´s what I have to tell abut what a before-unknown-now-known chemical term
Look on your products´ ingredients and locate Propylen Glycol!
References:
Propylene Glycol, Natural Health Care, consulted 12-08-2010, http://www.natural-health-information-centre.com/
 Propylene Glycol, FAO Corporate Document Repository, consulted 12-08-2010, http://www.fao.org/

Scientific Method :)

Wednesday´s class we just talked about some examples about some scenarios on which we had to apply the scientific method, actually it was just a review for me, because I used that method the last two semesters...I analyzed the four scenarios and got the problem, then I thought about it and got and Hypothesis, after that I just listed the experimentation to prove the hypothesis and identified the independent and dependent variable...
That´s what I did on my third class of Chemistry Something interesting Huh?! ;)
Wait for the next entry!! :D
Au Revoir!

"Because Matter matters" -(Teacher)

I was very Optimistic because of my class of chemistry on Tuesday, when I arrived to the math classroom in the morning a friend of mine and me realized an interesting question on the board (because of a chemistry class before my math class in the same room), it said "What is matter?" Immediately my friend said "Everything that has mass and occupies space" and I just tought ...WOW now I remember that.
After the repetition of that definition on my mind all day, the chemistry class finally arrived and what the teacher assigned was to make a conceptual map about...Guess What?... MATTER!! But the issue was that I had no Book and my only source to the internet was my iPod, what a problem, I had a hard time trying to remember some things, but I was pretty sure about the matter (:D) that matter has 3 states, solid, liquid and gas, but I needed information about physical and chemical changes and properties. But later I just chatted with my mates and got to the point that physical changes are the ones that doesn´t change matter´s nature, they just change its outer form...and chemical changes are the ones that transform the nature of matter... A great introduction for a hopefuly GREAT semester at Chem class! :)
I loved to remember that ...
It´s great to get back on the business of Chem!!!
Stay connected ;)

Beginning the course!!

When I was making the scheduele for my thied semester at High school, I realized that I would have Chemistry class, and as facebook would said...LIKE! I love chemistry since I was between 7 or 8 years old...actually I had my own chemistry set...IT WAS WONDERFUL, I had great times mixing strange sustances and materials to get a stinky mixture.
Although I loved all that stuff I never learned chemistry as I should have...but in junior high I had my first Chemistry course and I learned a lot.
The first day at Highschool arrived I was ready for every class, and Chemistry was my last class that day, and something that got into my mind immediately...was the first sentence of the teacher..."If you are in love...forget it, it´s just a chemical reaction..." haha that´s what he said and it got me thinking: not just love is chemistry (yes, that´s why is complicated sometimes...I believe...) EVERY single thing in this world has something to do with chem... so just put a little bit of attention and you will realize that...
You are dealing with Chemistry!!
Everyone in the world has to do with chemistry, actually we have chemistry inside us, we are making use of chemistry when we light up a candle, or when we cook!!! Not just those guys on whithe coats closed on research laboratories practice the cheistry...Think about it and keep track on the cheistry AROUND YOU!
Keep an eye on the blog...and read me please, I promise I´ll do my best to keep you entertained :)
bye! (: