Underneath the wonderful branch of chemistry, nuclear chemistry, there is a branch known as, nuclear physics, that help explain some of the phenomena that occur in nuclear reactions and processes. These are new concepts for me being a young researcher out on the internet exploring different topics underneath nuclear chemistry so bare with me reader as we take a dive into what seems to be a concept that reaches far beyond my level of comprehension.
To start out, after doing some general research overlooking the topic, I’d like to address some key terms that I may mention in drafting this blog post. First, a nucleon is one of the subatomic particles of the atomic nucleus, i,e. a proton or a neutron. Second, being one of the main focuses of this post, mass defect, which is the difference between the calculated mass of the unbound system and the experimentally measured mass of the nucleus. Third, strong force, being the nuclear force, a residual force responsible for the interactions between nucleons, deriving from the color force. Now that you may have a small idea of what is going on, perhaps the reading of this post will go a little more smoothly.
Nuclear binding energy is the energy required to split a nucleus of an atom into its component parts: protons and neutrons, or, collectively, the nucleons. As seen in fission, this is the process that is the cause of the releasing of high amounts of energy when the nucleus splits. If you are wondering what the magnitude of energy that results of fission can bring, I recommend checking out Mack Nason’s blog post on atomic bombs in World War II for a better reference on specific ways this process can be used. The binding energy of nuclei is always a positive number since all nuclei require net energy to separate them into individual protons and neutrons. To find the nuclear binding energy of an atom’s nucleus you first must find the mass defect. Nuclear binding energy accounts for a noticeable difference between the actual mass of an atom’s nucleus and its expected mass based on the sum of the masses of its non-bound components. Recall the famous equation by Albert Einstein, E=mc2 where energy (E) and mass (m) are related by the equation. Here, c is the speed of light. In the case of the nuclei, the binding energy is so great that it accounts for a significant amount of mass. The actual mass is always less than the sum of the individual masses of protons and neutrons because energy is removed when the nucleus is formed. This energy has mass, which is removed from the total mass of the original particles. This mass, known as the mass defect, is missing in the resulting nucleus and represents the energy released when the nucleus is formed. Mass defect (Md) can be calculated as the difference between observed atomic mass (mo) and that expected from the combined masses of its protons (mp, each proton having a mass of 1.00728 amu) and neutrons (mn, 1.00867 amu): Md=(mn+mp)−mo.
Once the mass defect is known, nuclear binding energy can be calculated by converting the mass to energy by using E=mc2 as stated earlier, Once this energy is known, it can be scaled into per-nucleon and per-mole quantities. Nuclear binding energy can also apply to situations when the nucleus splits into fragments composed of more than one nucleon (fission). In these cases, the binding energies for the fragments, as compared to the whole, may either by positive or negative, depending on where the parent nucleus and the daughter fragments fall on the nuclear binding energy curve. If new binding energy is available when light fuse, or when heavy nuclei split, either of these processes result in the release of the binding energy. This energy, available in nuclear energy, can be used to produce nuclear power or build nuclear weapons. When a large nucleus splits into pieces, excess energy is emitted as photons, or gamma rays, and as kinetic energy, as a number of different particles are ejected. This again gives more insight to a previous blog post by Mack Nason that I had read prior to drafting this blog post, so I am glad I got to dive a little more in depth at the specific process on how the energy is released. The nuclear binding energy curve determines whether or not fission or fusion will be a favorable process for that element or isotope. For elements lighter than iron-56, fusion will release energy because the nuclear binding energy increases with increasing mass. Elements heavier than iron-56 will generally release energy upon fission, as the lighter elements produced contain greater nuclear binding energy. As the size of the nucleus increases, the strong force is only felt between nucleons that are close together while the repulsion continues to be felt throughout the nucleus. This leads to instability and hence the radioactive nature of the heavier element.
Nuclear Binding Energy Curve and Fission vs. Fusion
Calculating Nuclear Binding Energy and Mass Defect Video:
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Hello Garret, I read your article and found it quite informative. Your explanation of the various concepts and terms of nuclear chemistry was quite useful when reading other articles relating to the branch. Your post also lead to mnason's post which discussed the Manhattan project and the two nuclear bombs used on Japan in WWII. When you mentioned subatomic particles which left me pondering. Later on I found Tushark's entry relating to quarks another type of subatomic particle. The combination of these three articles provides a cohesive conglomerate that epitomizes perfectly the branch of nuclear physics as well as illustrating its effects and utilization throughout history.
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