Cosmic/Nuclear Chemistry

This unit focused on diving into the basic building blocks of chemistry. We studied atomic structure, radioactive decay, stars, and much more revolving around the smallest unit of matter: the atom. Through worksheets, slideshows, notes, models, etc., we were able to deepen our understanding on all these topics and how they connected to our lives! We can see how atoms make up the entire world we live in and everything in it, including us! So expanding our knowledge of this tiny, but hugely important thing was extremely interesting!

My favorite topic we studied revolved around radioactive decay. Radioactive decay is the spontaneus disintegration of an atomic nucleus into a slightly lighter nucleus. In the process, they will release energy and matter from their nucleus and often transform into a new element. There are many different components and types of decay: alpha decay, beta decay, positron emission, electron capture, and gamma emission. Each of these modes of decay leads to the formation of a new nucleus with a more stable n:p ratio.

Alpha (α) decay is the emission of an α particle from the nucleus. When a nucleus is too large, an alpha particle is released. For example, polonium-210 undergoes α decay:

210 4 206

84 Po⟶2 He + 82 Pb

Beta (β) decay is the emission of an electron from a nucleus. This process occurs when atoms are unstable because they have too many neutrons compared to protons. Iodine-131 is an example of a nuclide that undergoes β decay:

131 0 131 131 0 131

53 I⟶−1 e + 54 Xe or 53 I ⟶ −1 β + 54 Xe

Positron emission (β⁺ decay) is the emission of a positron from the nucleus. It occurs when atoms are unstable because they have too many protons. Oxygen-15 is an example of a nuclide that undergoes positron emission:

15 0 15 15 0 15

8 O ⟶ +1 e + 7 N or 8 O ⟶ +1β + 7 N

Electron capture occurs when one of the inner electrons in an atom is captured by the atom’s nucleus. There is an unstable nucleus because it has too many protons. For example, potassium-40 undergoes electron capture:

40 0 40

19 K + −1 e ⟶ 18 Ar

Gamma emission (γ emission) is observed when a nuclide is formed in an excited state and then decays to its ground state with the emission of a γ ray, a quantum of high-energy electromagnetic radiation. It often occurs after other types of decay where gamma rays are emitted from the nucleus. Cobalt-60 emits γ radiation:

60 0 60

27 Co ⟶ 0 γ + 27 Co

This unit has definitely been a huge, helpful factor in improving my problem solving skills, as well as collaboration with others. There were definitely times where I struggled with this unit, and felt myself getting lost and wanting to give up. But with help from my teacher and peers, I pushed through and thought critically to work through challenges. Now, at the end of the unit, I can confidently say I am a better problem solver and more perserverant student. I also worked on my group work skills as we would constantly complete assignments with partners or our table groups. Practice collaborating and getting work done did help me learn and taught me more ways to use my peers as resources. I believe I showed growth in the 6 C's because every obstacle, frustration, confusion, etc. taught me different ways to get through it and figure it out. I grew as a student and deepened my knowledge of chemistry on many levels.

Something I think I did well with was maintaining a good work ethic. All my assignments were always on time and completed with hard work and genuine effort. I used class time efficiently and was good at staying focused and always doing my best. Every worksheet was on time, any project was thoroughly completed, and all notes were taken with detail and in depth. Another aspect I think I succeeded in was asking questions. I was devoted to the work and actually wanted to understand. I asked several questions on a daily basis and made sure I was understanding the topics. If I was confused, I would utilize a peer or get my teacher. For example, I found myself struggling with our study of half-life problems, so I would end up raising my hand a lot and working with my teacher through the problem until it made sense. Not being afraid of asking questions was something that really helped me learn and get through a challenging unit.

Something I still need to improve on is my leadership skills. I tend to be timid and shy at times, especially when working with people I don't really know while trying to solve a problem I don't really understand. I need to learn to be more assertive and speak up to work through the assignment. My goal is to do this throughout the next unit and improve my communication skills as much as I can and be a leader among my new table group. Another thing I could work on is my presenting. I would not consider myself a great public speaker. I get anxious and shake, sweat, lose my breath, etc.. For example, when presenting a sildeshow about JJ Thompson, I had a hard time getting through the words without revealing the shakiness in my voice. In future presentations, I would like to be better at avoiding these things and be more confident in front of the class.

Overall, this unit has taught me many things, about chemistry as well as myself as a student. I know I will be able to take these skills with me to further benefit me in my school life!