Radioactivity Flashcards
Explain concept of linear energy transfer
What is radioactivity?
Radioactivity is the act of emitting radiation spontaneously.
Why does the nucleus of an atom become unstable?
The nucleus of an atom becomes unstable when it either has excess nucleons or excess energy.
How does an unstable nucleus try to become stable?
The nucleus tries to become stable by emitting either energy or nucleons.
What is the smallest unit into which matter can be divided without the release of electrically charged particles?
The atom is the smallest unit into which matter can be divided without the release of electrically charged particles.
What is the smallest unit of matter that has the characteristic properties of a chemical element?
The atom is the smallest unit of matter that has the characteristic properties of a chemical element.
What is the basic building block of chemistry?
The atom is referred to as the basic building block of chemistry.
What particles does a nucleus have?
A nucleus has nucleons, which include protons and neutrons.
What is the symbol for atomic mass number?
The symbol for atomic mass number is ‘A’.
What is the symbol for proton number?
The symbol for proton number is ‘Z’.
What is the symbol for neutron number?
The symbol for neutron number is ‘N’.
How can a specific nucleus or ‘nuclide’ be specified?
A specific nucleus or ‘nuclide’ can be specified using notation.
Why is the total mass of a stable nucleus always less than the sum of the masses of its separate pieces?
Energy, as radiation or kinetic energy, is released during the formation of a nucleus by the ‘fusion’ of smaller nuclei, giving a net mass difference.
What is the force that binds nucleons together?
The force that binds nucleons together is called the strong nuclear force.
What is the range of the strong nuclear force?
The strong nuclear force is a very short-range force, essentially zero if the nucleons are more than about 10^-15 meters apart.
Why are extra neutrons needed for the stability of high-Z nuclei?
Extra neutrons are needed for stability because the Coulomb force is long-range.
What governs the decay of unstable nuclei?
Unstable nuclei decay, and some decays are governed by the weak nuclear force.
What are the three types of radioactive decay?
The three types of radioactive decay are alpha decay, beta decay, and gamma decay.
How do alpha and beta rays behave in a magnetic field compared to gamma rays?
Alpha and beta rays are bent in opposite directions in a magnetic field, indicating opposite charges, while gamma rays are not bent at all.
What occurs during alpha decay?
In alpha decay, the nucleus emits a helium-4 nucleus (an alpha particle).
When does alpha decay most often occur?
Alpha decay most often occurs in massive nuclei that have too large a proton to neutron ratio.
Why is an alpha particle a stable configuration of particles?
An alpha particle, with its two protons and two neutrons, is a very stable configuration of particles.
How does the decay of 210Po by alpha emission change the nucleus?
The decay of 210Po by alpha emission changes the nucleus to 206Pb, reducing the proton to neutron ratio and making it more stable.
What happens to the atomic number during alpha decay?
The atomic number changes during alpha decay, so the original (parent) atoms and the decay-product (daughter) atoms are different elements with different chemical properties.
What appears as the kinetic energy in alpha decay?
The change in binding energy appears as the kinetic energy of the alpha particle and the daughter nucleus.
Why does most of the kinetic energy go to the alpha particle in alpha decay?
Most of the kinetic energy goes to the alpha particle because it has a smaller mass than the recoiling nucleus.
When does alpha decay occur in terms of nuclear force?
Alpha decay occurs when the strong nuclear force cannot hold a large nucleus together.
What is the disintegration energy in alpha decay?
The disintegration energy is the difference in mass between the parent nucleus and the sum of the daughter nucleus and the alpha particle.
When does beta decay occur?
Beta decay occurs when a nucleus emits an electron or positron.
What are beta particles?
Beta particles are electrons or positrons (electrons with a positive electric charge, or antielectrons).
What happens during beta minus decay?
In beta minus decay, a neutron decays into a proton, an electron, and an antineutrino.
What happens during beta plus decay?
In beta plus decay, a proton decays into a neutron, a positron, and a neutrino.
Why do particular beta decay reactions take place?
These reactions take place because conservation laws are obeyed, such as the conservation of electric charge and lepton number.
What is beta minus decay in the context of phosphorous 32?
Phosphorous 32 undergoes beta minus decay by transforming an excess neutron into a proton, forming the stable isotope sulphur 32.
What is beta plus decay in the context of neon 19?
Neon 19 undergoes beta plus decay, having 10 protons and 9 neutrons.
What is electron capture?
Electron capture is a type of beta decay where an orbital electron is pulled into the nucleus and combines with a proton to form a neutron.
What particle is emitted during electron capture?
The only particle emitted during electron capture is a neutrino.
What does the nucleus do with excess energy after electron capture?
The nucleus releases excess energy by emitting gamma radiation, leaving it in an excited state.
What happens during gamma decay?
In gamma decay, a nucleus changes from a higher energy state to a lower energy state through the emission of electromagnetic radiation (photons).
Does the number of protons or neutrons change in gamma decay?
No, the number of protons and neutrons in the nucleus does not change during gamma decay, so the parent and daughter atoms are the same chemical element.
