Unit 3 Study Guide Notes
1. Origin of Elements
All elements originate from nuclear fusion in stars and supernova explosions.
2. Charges of Subatomic Particles
Protons (P+): positive charge
Electrons (e-): negative charge
Neutrons: neutral charge (no charge)
3. Subatomic Particles in the Nucleus
The nucleus contains:
Protons
Neutrons
4. Isotopes
Definition: Isotopes are different versions of the same element.
They have:
Same number of protons
Different number of neutrons
5. Identifying Subatomic Particles in Atoms/Isotopes
Electrons and protons: the number of these equals the atomic number of the element.
Neutrons calculation:
6. Radioactive Elements on the Periodic Table
Elements with an atomic number greater than 83 are typically radioactive.
7. Causes of Instability in Radioactive Isotopes
Instability is caused by an unstable ratio of protons to neutrons, leading to an imbalance.
8. Isotope Notation
Isotope notation is written in the form: Element-Atomic Mass.
9. Subscript or Superscript in Isotope Notation
The superscript represents the atomic mass (mass number).
The subscript, if present, indicates the atomic number.
10. Band of Stability for Isotope Stability
Isotopes in the band of stability must have a stable ratio of protons to neutrons.
11. Band of Stability for Isotope Instability
Isotopes outside the band of stability are considered unstable.
12. Real Isotopes and the Band of Stability
Combinations of protons and neutrons that fall out of the band of stability can still be considered real isotopes but are unstable.
13. Isotopes with 1:1 Ratio of Protons to Neutrons
Light isotopes (specifically for elements with low atomic numbers, typically those around carbon, nitrogen, and oxygen) often exhibit a close 1:1 ratio of protons to neutrons.
14. Decay Patterns of Unstable Isotopes
Unstable isotopes decay at random intervals unpredictable compared to the notion of half-life. This randomness reflects the nature of radioactive decay.
15. Changes during Different Types of Decay
Alpha Decay:
Emission of an alpha particle (2 protons and 2 neutrons, essentially a helium nucleus).
Beta Decay:
A neutron is converted into a proton and an electron (beta particle is ejected).
Gamma Decay:
Release of gamma radiation (high-energy photons).
16. Releases in Types of Decay
All types of decay release energy in the form of particles or radiation, specifically:
Alpha particles, beta particles, and gamma rays.
17. Radioactive Isotopes with Atomic Number ≤ 83
Elements with an atomic number of 83 or less can indeed have radioactive isotopes.
18. Definition of Radioactive Decay
Radioactive decay is the process by which an unstable atomic nucleus loses energy by emitting radiation.
19. Definition of Radiation
Radiation is energy that travels through space and may come in the form of particles (alpha, beta) or electromagnetic waves (gamma).
20. Graphing Radioactive Isotopes
A suitable graph to show the percentage of radioactive isotopes left during multiple half-lives is a logarithmic or exponential decay graph.
21. Axes for Graphing
X-axis: Time (in half-lives)
Y-axis: Percent of Radioactive Isotope Remaining
22. Line Characteristics of M&M Data on Graph
The plotted line from the data should illustrate an exponential decay trend, decreasing as the number of half-lives increases.
23. Definition of Half-Life
Half-life is the time required for half the quantity of a radioactive isotope to decay into another substance or isotope.
24. Half-Life Variability Among Isotopes
No, not every isotope has the same half-life; each isotope possesses a unique half-life based on its stability.
25. Similar Graphs for Isotopes
No, each isotope would represent a different graph when showing the percentage of isotope remaining over elapsed half-life due to differing decay constants.
26. Definition of Nuclear Chemistry
Nuclear chemistry is the study of the chemical and physical properties of elements as influenced by changes in the structure of the nucleus.
27. Types of Nuclear Reactions
The two primary types of nuclear reactions are:
Fusion reactions
Fission reactions
28. Fusion Reaction Process
A fusion reaction occurs when two light atomic nuclei combine to form a heavier nucleus, resulting in the release of a significant amount of energy.
29. Fission Reaction Process
A fission reaction occurs when a heavy nucleus splits into smaller nuclei, along with the release of energy and neutron emissions.
30. Commonalities between Fusion and Fission
Both reactions release vast amounts of energy; they convert mass into energy according to the principles of Einstein's equation, .
31. Chernobyl Accident Year
The Chernobyl disaster occurred in April 1986.
32. Explosion at Chernobyl
The explosion at the Chernobyl nuclear power plant was a result of a reactor core explosion.
33. Physical Injuries in Chernobyl
Many individuals experienced severe physical injuries such as burns due to exposure to high levels of radiation released by the explosion.
34. Handling of the Chernobyl Explosion
The government officials attempted to contain the incident by evacuating nearby inhabitants and controlling the spread of radioactive contamination.
35. Nuclear Reaction in Nuclear Reactor
Nuclear fission occurs in the core of a nuclear reactor.
36. Nuclear Chain Reaction Definition
A nuclear chain reaction is a process in which a single nuclear reaction causes a successive series of nuclear reactions.
37. Subatomic Particle for Chain Reaction Initiation
Neutrons are the subatomic particles necessary to initiate a nuclear chain reaction.
38. Fire Usage at Nuclear Power Plants
No, traditional fire is not used as the primary energy source at a nuclear power plant; instead, the energy generated comes from nuclear fission reactions.
39. Energy Use in Nuclear Reactions
The energy released from the nuclear reactions is used to generate heat, which then turns water into steam for driving turbines to produce electricity.
40. Liquid Used in Nuclear Power Plants
Water is the primary liquid used in nuclear power plants, serving both as a coolant and to produce steam.
41. Uranium Enrichment Definition
Uranium enrichment is the process of increasing the proportion of uranium-235 isotope in uranium fuel to make it usable in a nuclear reactor.
42. Purpose of Uranium Enrichment
Scientists enrich naturally occurring uranium to ensure that the percentage of uranium-235 is high enough to sustain a chain reaction in the reactor.
43. Preparation of Enriched Uranium for Reactors
After achieving the correct percentage of uranium-235, it is formed into fuel pellets before being assembled into fuel rods for use in a reactor, rather than just dumping it directly into the reactor.
44. Order of Fuel Components
From smallest to largest:
Fuel pellets
Fuel rods
Fuel assemblies
45. Chronological Order of Nuclear Power Plant Operations
1. Nuclear fission in the core.
2. Heat from fission creates steam.
3. Steam spins the turbine.
4. Turbine spins the generator.
5. Generator spins and creates electricity.
46. Composition of Control Rods
Control rods are often made of materials such as boron, cadmium, or hafnium.
47. Absorption by Control Rods
Control rods absorb neutrons to regulate the fission reaction within the reactor.
48. Purpose of Control Rods
The purpose of control rods is to manage and control the rate of the nuclear fission reaction, ensuring it does not escalate dangerously.
49. Desired Core Temperature
Operators aim to maintain the core temperature at around 2000°F (about 1093°C).
50. Water Usage in Reactors
In addition to generating steam, water is used in the reactor as a coolant to prevent overheating of nuclear materials.
51. Purpose of the Containment Building
The containment building serves to contain the radiation and reactor materials within the facility, protecting the surrounding environment and population from exposure in the event of an accident.