Question

Which types of radioactive decay cause the transmutation of a nuclide? (Hint: Review the definition of transmutation.)

Short answer

Alpha decay and beta decay (beta-minus and beta-plus) cause transmutation.

Step-by-step solution

- Understand Transmutation

Transmutation is the process by which a nucleus of one element changes into a nucleus of a different element. This involves a change in the number of protons in the nucleus.

- Identify Types of Radioactive Decay

Review the main types of radioactive decay: alpha decay, beta decay (beta-minus and beta-plus), and gamma decay.

- Determine Which Decay Causes Transmutation

Alpha decay and beta decay (both beta-minus and beta-plus) change the number of protons in the nucleus. Alpha decay decreases the proton number by two, while beta-minus decay increases the proton number by one, and beta-plus decay decreases it by one. Gamma decay does not change the number of protons and thus does not cause transmutation.

- Summarize the Findings

Only alpha decay and beta decay (beta-minus and beta-plus) cause the transmutation of a nuclide. Gamma decay, however, does not affect the number of protons and therefore does not cause transmutation.

Key concepts

Alpha Decay

Alpha decay is a type of radioactive decay where an unstable nucleus emits an alpha particle. This alpha particle consists of 2 protons and 2 neutrons. When a nucleus undergoes alpha decay, it loses 2 protons and 2 neutrons.
As a result, the original element changes into a different element, specifically one that is 2 places back on the periodic table.
For example, when Uranium-238 undergoes alpha decay, it turns into Thorium-234.
This process results in the atomic mass decreasing by 4 units, due to the loss of 2 protons and 2 neutrons.
Thus, alpha decay is a potent method of transmutation, as it directly changes the number of protons in the nucleus.

Beta Decay

Beta decay comes in two forms: beta-minus (β⁻) and beta-plus (β⁺).
In beta-minus decay, a neutron in the nucleus is transformed into a proton while emitting an electron (called a beta particle) and an antineutrino. This increases the atomic number by one, thus changing the element into a new one that is one place forward on the periodic table.
For example, Carbon-14 decays to Nitrogen-14.
In beta-plus decay, a proton is converted into a neutron, a positron (the electron’s antimatter counterpart), and a neutrino. This decreases the atomic number by one, resulting in a new element that is one place back on the periodic table.
For instance, when Carbon-11 undergoes beta-plus decay, it turns into Boron-11.
Both types of beta decay involve transmutation as they change the number of protons in the nucleus.

Nuclear Transmutation

Nuclear transmutation is the process where one chemical element or isotope is transformed into another.
This usually happens via nuclear reactions, including radioactive decay like alpha and beta decay.
Transmutation changes the number of protons in the nucleus, leading to the formation of a new element.
Originally, humans mainly observed natural transmutation processes, such as how Uranium naturally decays into Lead over long periods of time.
Today, scientists can also induce transmutation artificially. This is done in particle accelerators or nuclear reactors by bombarding targets with particles.
For example, artificially changing elements is used for medical isotope production or even for energy production in nuclear reactors.
Overall, the key takeaway is that both alpha decay and beta decay are critical processes for transmutation, while gamma decay doesn't change the number of protons and thus doesn't cause transmutation.