Finishing Up Radioactivity

We finished off the Atomic Structure and Radioactivity unit today. The unit was concluded with a unit exam composed of 36 questions. The test was very easy except for one single problem: how many alpha emissions would it take for 238/92 U to decay into 208/82 Pb. The answer was either 2,4,6,9 or none. (Please comment what you think the answer is, just curious). The test did have a rather large amount of questions over radioactive decay. I didn't mind being that I actually think radioactive decay is very interesting. Check out this link to learn more on alpha and beta decay: here. Can't wait to see what this next unit has in-store for us.

Half Life

All radioactive elements are subject to devolve into an element of less protons and atomic mass. The amount of time it takes s for half of a sample to devolve is called a half life. Some elements can take numbers of years or centuries to decompose while others can in a matter of seconds. For example, carbon 14's half life is 5730 years. The half life of an isotope can be expressed though a basic exponential algorithm.

http://www.coolmath.com/algebra/17-exponentials-logarithms/13-radioactive-decay-decibel-levels-01

Elements with half lives can be applicable to many functions that we use in our world. It's amazing to think about all that these simple particles can actually accomplish.

Isotopes

      One of the flaws in Dalton's five points about chemistry is that all atoms of a single element are identical. The number of protons in the nucleus will be the same, but the number of neutrons can vary among atoms of the same element. The various amounts of neutrons in the nucleus, which have a neutral charge, create various isotopes of an element. These isotopes will also vary in mass as well as neutrons.

                                                http://www.ducksters.com/science/chemistry/isotopes.php
       To name an isotope, you must use isotope notion. It displays the symbol of the element, the mass number (sum of protons and neutrons) on the upper left, and the atomic number (number of protons) on the bottom left.

http://thechemguys.blogspot.com/2011/04/april-18-atomic-mass-and-isotopes.html

Dalton's Atomic Theory

Composed over two centuries ago, was the first theory to what makes up everything around us. The man behind this was John Dalton. Even though Dalton's theory contains a few flaws, it is the basis of modern chemistry.

His theory was made into five points:

1. All elements are made up of atoms, which is still known to be a true statement.
2. All atoms of a single element are identical, which has been proven false with the discovery of isotopes.
3. Atoms of different elements are different, which is still true.
4. Compounds are made up of different elements, which is also true.
5. Atoms are indivisible and aren't created nor destroyed. Atoms can be divisible since subatomic particles such as the quark have been discovered. However, atoms still must abide to the law of conservation of matter, making the second part of the statement true.

His work has lead others to further his discovery and evolve the expanding universe of chemistry. 

Evolving Theories