Chem Blogger #2!

What am I struggling with? In chemistry this week, I would say that I am struggling with the concept of how the cathode tube explained electrons. I understand their charge and how they appear on the atom. I guess what I really don't understand is Rutherford's experiment, how he came to understand that the "mass and positive charge must be concentrations a small fraction of the total volume of the atom"(Trisha, class lecture 9/2).
I understand the structural concept of the atom, and how to read the periodic table. J.J. Thompson's "Plum Pudding" model brings back high school chemistry, which I understand and can picture. The part of lecture that intrigued me the most was Dalton's postulates. I find them amazing, and every postulate makes perfect sense to me. What is fascinating is that he wrote these postulates with a very limited amount of technology and education.
I feel that I am learning the most important things in chemistry, how we came about and why they are. If we were to jump right into chemistry without any background, as in high school I would feel unprepared. I feel that the things we are learning are essential and interesting. I never knew that Dalton had started teaching science at the age of twelve. I always knew the mass of an electron, but had no idea how and who discovered it. But now, I know it was all thanks to cathode ray tubes, oil droplets, and Robert Millikin.
Ok, maybe not directly to my life does the mass of an electron or cathode ray tubes relate, but what I am learning is a stepping stone to what I will need to know further down the line in my studies of biology. These experiments relate directly to my life, because our chemistry lab will be asking us to think like these chemists had thinks when they were in the lab.
The current model of the atom came to be by the experiments of Ernest Rutherford, J.J. Thompson, Wilhelm Wie, Eugen Goldstein, and Robert Millikin. Each of them had contributions to how the atom is considered today. Rutherford found that the mass and positive charge was only a small amount of the total volume of the atom. Using radioactivity and the plum pudding model, Rutherford found that an atom is mostly space filled with electrons. He then went on to name the center of an atom the nucleus. Chadwick later went to find that there was more to the nucleus than positively charged protons, but neutral particles, name neutrons. Millikin found the charges from oil droplets and found the mass of an electron to be 9.109 * 10-28 g. J.J. Thompson created the Plum Pudding model to show his view of how the atom is set up by the results of his experiments with the cathode rays, finding that they can be bent by electric fields. Also, he found that they were negatively charged, which provided him with an estimate of the charge to mass ratio.
Dalton's postulates have been modified since the original only slightly. Number 1: Everything is made up of atoms, but atoms are not indivisible. There are subatomic particles, called protons, neutrons, and neutrons. Number 2: Atoms cannot be created or destroyed. True, but in nuclear reactions chemicals can become other atoms. Number 3: All atoms have the same number of protons. But, there are such things as isotopes, elements with the same number of protons, but they differ in number of neutrons. Number 4: Compounds are formed by chemical combination, now the only change is that some have different atom ratios. These are significant because now we know that atoms are not the smallest particles of life. Now we know what makes one atom different from the other, the number of protons. To know that atoms can convert into other atoms is important, now scientists are not limited to certain elements, now they have the ability to change certain ones in nuclear reactions. The isotopes are the same type of element, only with a different number of neutrons, not changing the charge of the atom, only varying the mass slightly.