Questions and Answers
What happens to isotopes when they decay?
Which of the following elements is the final product of the decay chain of uranium-238?
Why is exposure to radiation considered dangerous?
In what way is carbon-14 used scientifically?
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Which of the following statements about bismuth is true?
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Who is credited with the discovery of radioactivity?
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What defines an unstable isotope?
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Which type of radiation is emitted in alpha decay?
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What is measured in curies (Ci)?
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What happens during beta decay?
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What can be said about the half-life of carbon-14?
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During gamma decay, what is emitted from the nucleus?
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Which of the following best describes a stable isotope?
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What is the role of the curie unit in radioactivity?
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Study Notes
Radioactivity Overview
- Isotopes are variants of elements with the same number of protons and electrons but differing neutron counts.
- Stable isotopes are common in nature, while unstable isotopes are termed radioactive.
Types of Radioactive Decay
- Alpha Decay: Occurs when there's an excess of protons; emits positively charged alpha particles.
- Beta Decay: Arises from too many neutrons; results in the emission of negatively charged beta particles.
- Gamma Decay: Happens when there's excess energy in the nucleus; gamma particles, which have no overall charge, are released.
Measurement of Radioactivity
- Radioactivity is quantified in curies (Ci), indicating the number of atoms decaying per second, named after Marie and Pierre Curie.
Half-Life Definition
- The half-life is the average duration required for half of a sample's atoms to undergo decay.
- Example: Carbon-14 has a half-life of 5730 years, meaning half of 1000 atoms are expected to decay over this period, not guaranteeing exact decay timing.
Radioactive Decay and Element Transformation
- Isotopes can decay into different elements, sometimes transforming into other unstable isotopes before becoming stable.
- The radioactive decay chain of uranium-238 passes through elements like thorium, radium, francium, radon, polonium, and bismuth, ultimately becoming stable lead.
Risks and Benefits of Radiation
- Radiation can mutate cellular structures, potentially leading to cancer; increased exposure heightens risks.
- Positive applications of radiation include medical imaging (X-rays), carbon dating for fossils, energy production, and sterilization processes.
Interesting Facts about Radioactivity
- Ground-level uranium decay produces radon gas, linked to being the second leading cause of lung cancer.
- Carbon-14’s half-life underpins fossil dating.
- Bismuth holds the title for the heaviest element with at least one stable isotope, with all heavier elements being radioactive.
- Radioactivity discovery credited to scientist A.H. Becquerel in 1896.
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Description
This quiz explores the concept of radioactive decay, focusing on how isotopes transform into different elements over time. Understand the average decay process and the implications of unstable isotopes in radioactive chains. Perfect for students studying nuclear chemistry or related fields.
