10.3 artificial transmutation this painting of an alchemist’s laboratory was made around 1570. for...
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10.3 Artificial Transmutation
This painting of an alchemist’s laboratory was made around 1570. For centuries, these early scientists, known as alchemists, tried to use chemical reactions to make gold. The alchemists failed in their attempts to turn lead into gold.
10.3 Artificial Transmutation
How do artificial transmutations occur?
Transmutation is the conversion of atoms of one element to atoms of another.
Scientists can perform artificial transmutations by bombarding atomic nuclei with high-energy particles such as protons, neutrons, or alpha particles.
Nuclear Reactions in the Laboratory
10.3 Artificial Transmutation
Transmutation involves a nuclear change, not a chemical change.
• Nuclear decay is an example of a transmutation that occurs naturally.
• Transmutations can also be artificial.
Nuclear Reactions in the Laboratory
10.3 Artificial Transmutation
In 1919, Ernest Rutherford performed the first artificial transmutation by exposing nitrogen gas to alpha particles.
• Some of the alpha particles were absorbed by the nitrogen nuclei.
• Each newly formed nucleus then ejected a proton, leaving behind the isotope oxygen-17.
Nuclear Reactions in the Laboratory
10.3 Artificial Transmutation
How are transuranium elements produced?
Elements with atomic numbers greater than 92 (uranium) are called transuranium elements.
Scientists can synthesize a transuranium element by the artificial transmutation of a lighter element.
Transuranium Elements
10.3 Artificial Transmutation
All transuranium elements are radioactive, and they are generally not found in nature.
Neptunium was the first transuranium element synthesized. In 1940, scientists at the University of California, Berkeley, bombarded uranium-238 with neutrons, producing uranium-239.
The uranium-239 underwent beta decay to form neptunium-239.
Nuclear Reactions in the Laboratory
10.3 Artificial Transmutation
Most transuranium elements have only been produced for research, but some are synthesized for industrial use.
• Americium-241 is a transuranium element used in smoke detectors.
• The decay of plutonium-238 is used to generate electrical energy in some space probes.
Nuclear Reactions in the Laboratory
10.3 Artificial Transmutation
In 1977, NASA launched Voyager 1 and Voyager 2 spacecraft to explore the outer solar system. They are powered by the alpha decay of plutonium-238.
Nuclear Reactions in the Laboratory
10.3 Artificial Transmutation
Some transmutations require particles that are moving at extremely high speeds.
Particle accelerators cause charged particles to move very close to the speed of light.
The fast-moving particles collide with atomic nuclei.
Scientists have produced more than 3000 different isotopes.
Particle Accelerators
10.3 Artificial Transmutation
Scientists also conduct collision experiments in order to study nuclear structure.
• More than 200 different subatomic particles have been detected.
• A quark is a subatomic particle theorized to be among the basic units of matter.
• According to the current model of the atom, protons and neutrons are made up of quarks.
Particle Accelerators
10.3 Artificial Transmutation
This particle detector records subatomic particles produced in the Tevatron, the most powerful particle accelerator in the world.
The Tevatron is located at Fermilab in Batavia, Illinois.
Particle Accelerators
10.3 Artificial Transmutation
Assessment Questions
1. Which of the following is a type of atom transmutation? a. alpha decay
b. gamma decay
c. chemical reaction
d. ionization
10.3 Artificial Transmutation
Assessment Questions
1. Which of the following is a type of atom transmutation? a. alpha decay
b. gamma decay
c. chemical reaction
d. ionization
ANS: A
10.3 Artificial Transmutation
Assessment Questions
2. To study the structure of the atomic nucleus, scientists use particle accelerators toa. combine small nuclei into larger nuclei.b. cause chemical reactions to occur rapidly.c. cause collisions of particles moving near the speed of
light.d. magnify nuclei so they can be studied on a computer
monitor.
10.3 Artificial Transmutation
Assessment Questions
2. To study the structure of the atomic nucleus, scientists use particle accelerators toa. combine small nuclei into larger nuclei.b. cause chemical reactions to occur rapidly.c. cause collisions of particles moving near the speed of
light.d. magnify nuclei so they can be studied on a computer
monitor.
ANS: C
10.3 Artificial Transmutation
Assessment Questions
1. Scientists make transuranium elements by the artificial transmutation of lighter elements.
TrueFalse
10.3 Artificial Transmutation
Assessment Questions
1. Scientists make transuranium elements by the artificial transmutation of lighter elements.
TrueFalse
ANS: T