What happens to a sample of an isotope during one half-life?
In one half-life approximately half the nuclei will decay into more stable nuclei.
How does CT technology differ from x-rays?
CT combines multiple x-ray images into a cross-sectional image of the body.
Name a manmade source of radiation. Provide 2 examples.
nuclear medicine, medical procedures, electronic devices, food irradiation devices.
What is a physical change?
Alter the appearance of a substance without changing its chemical composition.
Compare nuclear fission & fusion.
Fisson/fusion both nuclear reactions. Fission- splitting 2 or more smaller nuclei. Fusion- releases more energy than fission does.
What is a chain reaction?
Typically neutrons, from one reaction can start additional reactions.
Why are some isotopes stable while others are unstable & experience radioactive decay?
Strong forces holds P & N together in nucleus. Stable= proper ratio of N to P. Unstable= will decay nucleus with a lower energy state, which is more stable.
Why is it surprising that protons remain close together in the nucleus? What force is believed to hold these protons close to each other?
Protons= + charge, & like charges repel. The strong force holds the p's & n's together in the nucleus.
In what application of fission would supercritical mass be desired? Explain.
Supercritical mass -goal- fission weapon. The mass would allow the reaction to proceed uncontrolled producing a lot of energy in a short period of time.
What is a chemical change?
Alter the composition of compounds by breaking and forming chemical bonds to rearrange atoms into new substances.
Can we predict when a single atom of a radioactive isotope will decay? Explain.
No. Radioactive decay- random process-spontaneously. Half-life give the time of half of a sample to decay, doesn't allow us to predict future of decay event.
What happens to an atom during radioactive decay?
Spontaneously emits particles, energy, or both from its nucleus in order to become more stable
How does fusion impact our lives on Earth?
Fusion is essential to life on Earth. Fusion-nuclear reaction-energy from sun Energy is emitted into space-provides food energy for living organisms on Earth.
Summarize the discoveries that led to the discovery of radioactivity.
Wihelm Rontgen-x-rays in 1895. Henri Becquerel discovered radioactivity -studying x-rays. Ernest Rutherford/Paul Villard 3 forms of decay-alpha, beta, gamma
How do alpha and beta decay differ from artificial transmutations?
Both occur spontaneously, while artificial transmutations are manmade.