Nuclear Chemistry and Radioactivity Flashcards
7 cards from real CART practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Nuclear Chemistry and Radioactivity flashcards as text
Which type of radiation has the greatest penetrating power?
Answer: Gamma rays
Gamma rays are high-energy electromagnetic radiation with no mass or charge, allowing them to penetrate most materials except thick lead or concrete.
What particles make up an alpha particle?
Answer: 2 protons and 2 neutrons
An alpha particle is identical to a helium-4 nucleus, consisting of 2 protons and 2 neutrons, giving it a charge of +2.
When an atom undergoes alpha decay, what happens to its atomic number?
Answer: Decreases by 2
In alpha decay, the nucleus loses 2 protons (and 2 neutrons), so the atomic number decreases by 2.
Which statement best describes radioactive decay?
Answer: A nucleus spontaneously emits particles or energy to become more stable
Radioactive decay is a spontaneous process in which an unstable nucleus releases energy or particles to reach a more stable configuration.
What is the half-life of a radioactive isotope?
Answer: The time for half of the radioactive atoms in a sample to decay
Half-life is the time required for exactly half of the radioactive nuclei in a sample to undergo decay.
A beta particle emitted during beta-minus decay is identical to which particle?
Answer: An electron
A beta-minus particle is a high-energy electron emitted when a neutron in the nucleus converts to a proton.
If a radioactive sample has a half-life of 5 years, what fraction of the original sample remains after 15 years?
Answer: 1/8
15 years = 3 half-lives; after each half-life the sample halves: (1/2)^3 = 1/8 of the original remains.