L3 Particles And Radiation- Radioactive Decay (Overview) Flashcards
What type of nucleus is an alpha particle?
Helium Nucleus
Name the 3 types of radiation released by naturally occurring radioactive isotopes.
Alpha
Beta
Gamma
What does an alpha particle consist of? (In terms of constituents of an atom)
2 protons and 2 neutrons
What happens in alpha decay and what is the result?
The unstable nucleus of an element emits an alpha particle and forms a new nucleus which belongs to a different element.
What happens to the nucleon number of a nucleus which has emitted an alpha particle? Explain why.
Decreased by 4. Because alpha particle consists of 2 neutrons and 2 protons.
What happens to the atomic number of a nucleus which has emitted an alpha particle? Explain why.
Decreased by 2. Because alpha particle contains 2 protons.
Alpha emission happens in what kind of atoms?
Very big and very unstable atoms.
Above how many protons is the strong nuclear force not strong enough to hold the nucleus together?
82 protons
What form of energy is released in alpha decay and where does it go?
Kinetic energy. Majority goes to alpha particle and a little to decayed nucleus.
What does beta decay consist of?
Fast moving electrons that have a lot of energy
Why does the symbol for beta decay have a -1 as its atomic number and 0 as its mass number?
Because its charge is equal and opposite to that of the proton and its mass is much smaller than the proton’s mass.
What happens in beta decay and what is the result?
A neutron inside the nucleus changes into a proton therefore a beta particle is created in the nucleus and emitted at high speed. As such the product nucleus belongs to a different element.
As a result of beta decay, what happens to the atomic number?
Increases by 1
As a result of beta decay, what happens to the nucleon number?
Stays the same
An antiparticle is also emitted along with the beta particle during beta decay. What is this antiparticle and what is it an antiparticle of? Include 2 basic characteristics of these particles.
Antineutrino. Antiparticle of neutrino. Have no charge and nearly zero mass.
Beta decay happens to what kind of nuclei?
Nuclei that have too many neutrons.
What is gamma emission?
Electromagnetic radiation emitted by an unstable nucleus.
Gamma emission is the most penetrating because?
It can pass through thick metal plates.
State 2 characteristics of gamma emission.
No mass. No charge.
Gamma emission is often part of a 2 stage process, with alpha/beta preceding gamma emission. Explain why.
Because when a nucleus emits an alpha/beta particle it’s often left in an excited state (a state in which it has excess energy). In order to lose this energy and so become more stable, the nucleus may emit a gamma ray, an electromagnetic wave of very short wavelength.
What is the result of gamma emission?
The composition of the nucleus is unchanged in this process, and so the element itself remains unchanged.
