Glossary
Alpha Decay
A type of radioactive decay where an unstable nucleus emits an alpha particle, decreasing its atomic number by 2 and its mass number by 4.
Example:
Uranium-238 undergoes alpha decay to become Thorium-234, shedding two protons and two neutrons.
Alpha Particles
Particles consisting of two protons and two neutrons, identical to a helium nucleus, emitted during alpha decay. They carry a +2 charge.
Example:
When a heavy nucleus undergoes alpha decay, it ejects an alpha particle, reducing its atomic number by two.
Antineutrinos
The antiparticle of a neutrino, also electrically neutral with nearly zero mass, emitted during beta-minus decay.
Example:
In beta-minus decay, a neutron transforms into a proton, an electron, and an antineutrino to conserve energy and momentum.
Beta-Minus Decay
A type of radioactive decay where a neutron in the nucleus transforms into a proton, emitting an electron and an antineutrino. This increases the atomic number by 1.
Example:
Carbon-14 undergoes beta-minus decay to become Nitrogen-14, a process used in carbon dating.
Beta-Plus Decay
A type of radioactive decay where a proton in the nucleus transforms into a neutron, emitting a positron and a neutrino. This decreases the atomic number by 1.
Example:
Sodium-22 undergoes beta-plus decay to become Neon-22, a process that involves the emission of an antielectron.
Charge
A fundamental property of matter that determines electromagnetic interactions, which must be conserved in all nuclear reactions.
Example:
In beta-minus decay, a neutral neutron becomes a positive proton and a negative electron, ensuring the total charge remains zero.
Conservation Laws
Fundamental principles stating that certain quantities, such as the total number of nucleons, leptons, and overall charge, remain constant in nuclear reactions.
Example:
When balancing a nuclear equation, applying the conservation laws ensures that the sum of atomic numbers and mass numbers are equal on both sides.
Gamma Decay
A type of radioactive decay where an excited nucleus releases excess energy by emitting a high-energy photon (gamma ray), without changing its atomic or mass number.
Example:
After an alpha or beta decay, the resulting nucleus might still be in an excited state and then undergo gamma decay to reach its ground state.
Isotope
Atoms of the same element that have the same number of protons but different numbers of neutrons, leading to different mass numbers.
Example:
Carbon-12 and Carbon-14 are isotopes of carbon; they both have 6 protons but differ in their number of neutrons.
Leptons
A class of fundamental particles that includes electrons, positrons, neutrinos, and antineutrinos, which are conserved in nuclear decays.
Example:
During beta decay, the emission of an electron or positron along with a neutrino or antineutrino ensures the conservation of leptons.
Neutrinos
Electrically neutral subatomic particles with nearly zero mass that interact very weakly with matter, emitted during beta-plus decay.
Example:
Detecting a neutrino is incredibly challenging because it can pass through light-years of lead without interacting.
Neutron-to-proton ratio
The ratio of the number of neutrons to the number of protons within an atomic nucleus, which is a key factor in determining nuclear stability and decay pathway.
Example:
Nuclei with an unstable neutron-to-proton ratio often undergo beta decay to adjust this ratio and achieve greater stability.
Nucleons
Collective term for protons and neutrons, which are the constituent particles of an atomic nucleus.
Example:
In any nuclear reaction, the total number of nucleons (protons + neutrons) must be conserved.
Positrons
Also known as antielectrons, these are particles with the same mass as electrons but carrying a positive charge, emitted during beta-plus decay.
Example:
A PET scan uses the annihilation of positrons with electrons to create gamma rays, which are then detected to form images.
Radioactive Decay
The spontaneous process by which unstable atomic nuclei release energy and particles to transform into more stable nuclei.
Example:
The slow transformation of uranium into lead over millions of years is a classic example of radioactive decay.