Flame ON!

On a side note, today is also MOLE DAY! Happy 6.02 x 10^23!
This week we did a really cool flame test with different kinds of elements like Sodium and Boron.

They emitted different colors of flames when we burned them, such as bright candy red and bright lime green! This is because each element has a unique energy signature that gives off discrete photons when energy is added. In the case of copper, it emits green light because its energy level makes it emit a certain wavelength of light (with a specific amount of energy) that is green!

On another side note, my group accidentally left in the metal hoop for too long and it turned white hot. x_o

Einstein Cheated on His Wife

And married his cousin. :v

We were watching a really awesome movie this week about Einstein and E equals m c squared! It also had scientists like Michael Faraday (who discovered electromagnetivity), Lise Meitner (who studied radioactivity and discovered nuclear fission), and Emile du Chatelet (Voltaire's mistress who studied physics).

We also continued work on radioactivity with two worksheets, and learned about the band of stability, which shows where elements are likely to be stable. Anything with too many neutrons will likely beta decay, while having too few neutrons can result in electron capture (which makes gamma rays.) Finally, alpha decay results from very heavy elements (such as Uranium) just having too many protons and neutrons.

More Radiation!

This week, we continued learning about radiation.

Nuclear reactions can cause a chain reaction that is self-sufficient. When a radioactive element gives off neutrons as it decays, those high speed neutrons can slam into other stable atoms and cause them to decay as well. This process continues on and remains self-sufficient as long as the number of neutrons and atoms balances out. In science, this balance is called the critical mass. If one neutron causes less than one reaction, the process dies off. If the critical mass is too high, the reaction will eventually generate enough heat to cause a violent explosion.

Radioactive elements release a lot of energy: incredible amounts of it that tower over the amount of energy released from combustion (burning coals, fuels.) That's why research has gone into exploring possibilities of creating a more environmentally friendly energy source using nuclear power. Uranium and Plutonium are popular elements to use in these nuclear reactors to produce energy.

Nuclear reactors produce energy by using the energy given off to power steam turbines that generate electricity. While this creates efficient energy, there are risks and extreme dangers of nuclear reactors. If a reactor overheats, it can potentially explode and spew radioactive waste into the atmosphere. This radioactive waste can spread across large areas, and remain radioactive for a very long time, thus making the surrounding area completely uninhabitable. In the disaster of the Chernobyl in Austria, the explosion of a nuclear reactor spread nuclear waste all across Europe and made the city where Chernobyl was uninhabitable. Many people died in the explosion, and even more were sick with radiation poisoning and cancer. Even with these dangers, the huge amounts of energy produced by radiation still fuels further research.

Radioactivity

This week, we learned about radioactivity. It's when atoms decay because they become unstable into another stable element. This can be caused by a different number of neutrons, or when high energy particles slam into an atom and destabilize it. The most common kind of radiation is alpha particle decay, where decaying elements spit out alpha particles (4/2 Helium atoms) and lose 4 in mass number and 2 in atomic number. Beta decay is where it loses a beta particle (electron) and loses only 1 in atomic number.

Sometimes, radioactive decay can result in gamma ray production, which are just high energy particles with no weight and no charge. Light is an example of a gamma ray.

These radioactive atoms all have half-lives, which is the amount of time required for the sample to lose 50%. Carbon-14 has a half-life of around 5730 years, while Uranium-238 has a half life of 4.46 [b]billion[/b] years! Scientists and archaeologists can use these half-lives to date ancient artifacts and samples of matter.

Atoms are greedy

Yes they are.

Atoms have the same number of protons as their electrons, therefore they're neutral. However, atoms have a level of electronegativity and ionization energy. Electronegativity describes how greedy atoms of a given element are, or their tendencies to attract electrons. The trend of electronegativity increases from the bottom left to the top right of the table. The least electronegative atom is Cesium because it has the most electron shells, which makes it hold its electrons very loosely. Opposite Cesium is Flourine, with the highest level of electronegativity because it holds its many electrons very tightly. The noble gases generally do not have any electronegativity because their electron shells are full.

Ionization energy is the amount of energy it takes to remove an electron from an atom's outermost valence shell. Similar to the electronegativity trend, the amount of energy increases from the bottom left to the top right. Helium has the highest ionization energy because it holds its electrons very tightly and has its electron closest to the positive nucleus (because it only has one shell), and therefore it requires the most energy to pull the electron off.

Nucleus!

THIS this week, which is not this week, we learned about how atoms were discovered and what they -probably- look like. They're a really small particle unseen by the human eye, with an even smaller nucleus made up of protons and neutrons. (If the atom was a football stadium, the proton is only the size of a fly in the middle. :o)

Swirling around the nucleus are extremely tiny electrons in a giant cloud. The number of protons determines what kind of elemental atom it is, and the number of neutrons can make it a different kind of isotope. Atoms can lose or gain electrons and become cations and anions, respectively. The ones in Groups 1, 2, and 3 lose 1, 2, and 3 electrons to make 1+, 2+, and 3+ charged cations. They can merge with those in Groups 6 and 7, which gain 2 and 1 electron(s) to make ionic compounds. They can combine to make compounds like salt (NaCl)!

On Thursday, we watched a Simpsons parody of the Powers of Ten video. Apparently we all live inside Homer Simpson's hair cell, in his DNA. What if we get shaved off? :(

This week:

This week:



We learned about the periodic table. :O
It was invented in the 1700s by a scientist named Mendeleev (Men-dal-lay-yev)
The table is organized by trends that go from left to right and up to down. Most of the metals are on the left side, and the right side is nonmetals. If you go down a group, the reactivity, atomic size, and atomic mass get bigger (except for the halogens, where it goes from bottom up, with Flourine being the most reactive)~

If you go from left to right, the atomic size gets smaller but the mass gets bigger, because they have more protons and it makes the atom heavier but smaller at the same time. The alkali metals on the left are really reactive to water, while the noble gases at the very far right are completely unreactive~