Unit 10 Blog

1) Planck's Hypothesis says energy is released or absorbed in small packets, called photons. This theory helped Bohr create his model of the atom because there must be specific energy levels and specific paths for the electrons to travel on, due to these photons. Personally, this is the hardest concept to understand all unit because the photons could be seen as energy and particles at the same time.

2) The Plum Pudding Model included a wispy, positively charged nucleus with mobile electrons. However, this couldn’t be right because in the Gold Foil Experiment when the small positively charged particles were shot at the piece of gold foil, they usually went straight through although sometimes went slightly off course and rarely straight back to where they came from.
Rutherford’s model included the atom being made up of mostly space with a very small, positively charged nucleus and still including the electrons.

Using Planck’s hypothesis, Bohr created his new model that still had a small, positively charged nucleus, however this time he included electrons that had specific paths and energy levels.

His model was discarded because of Heisenberg’s Uncertainty Principle that stated it is impossible to know the position and speed of an object at the same time.

The Quantum Model is very similar to our modern day model, with a small, positively charged nucleus, as well as electrons that move around the nucleus in energy-specific orbitals (a region of space with a high probability of finding an electron). The only change made to this model was when protons and neutrons were discovered. They are both subatomic particles that make up the nucleus with a mass of about 1 amu, with the neutrons having no charge and the protons having a charge of +1.

I think it is cool how we made it from the Plum Pudding Model to the modern day model because they are so different, but there was only one small change made each time. It was a long process, but so are a lot of other science discoveries.

3) All of these examples of spectroscopy were caused by electrons getting excited after gaining energy, then releasing this energy in the form of light. Not all the colors are shown because each element has a different number of electrons at different energy levels, which represents different colors and frequencies. Before this unit, I knew that light was made up of waves, however I didn’t know that the electrons in the atom was actually what caused this light and colors.

Quarter 3 Reflection Blog

The first activity this week was the Molecular Model Activity packet. We learned how chemical equations are written, and focused on having the same numbers of each kind of atoms on both sides of the equations. For example, If we started with 4 Hydrogen atoms and 2 Oxygen atoms on the left side (the reactants) then we had to have exactly 4 Hydrogen atoms and 2 Oxygen atoms on the right side with the products. When we started, I knew that the equations had to be balanced, but I never understood why.

Just like the molecular model activity, this picture shows
that there are 2 O2 molecules needed to form the products. 

Next we worked on balancing equations. Before we could do this, we had to remember how to write molecular formulas correctly based off of the name. In order to balance equations we could only add coefficients in front of each compound; we can't adjust the subscripts. Then after some practice we learned some hints to make balancing the more complex formulas easier. The first hint we learned was to always adjust the coefficients of a single species last. This means if you have a single element such as Mg or O2, balance that atom last. This way, when you add a coefficient you are only changing the number of that element and not adding more of any other element/molecule. The second hint was "sometimes the temporary use of a faction or decimal is useful." This helps especially when you only need half of one compound. Then after everything is balanced, multiple by 2 throughout the whole equation to end up with whole numbers. The last hint was to balance polyatomic ions as units if they are on both sides of the equation, such as PO3, SO3, or NH4. With all of these hints, they help to balance equations without having to physically see the molecules like the first activity we completed.

The last activity we did was our Reaction completion lab. We had to try to figure out what the products were in our reactions based off of observations and tests such as splint tests and litmus papers. 

These concepts make sense to me, especially after the different activities. I think the molecular model activity helped the most to understand why and how we balance equations. The different sides of the arrow should be equal because that's how the reactions occur in nature due to the Law of Conservation of Mass.