Characteristics of the three types of emission Flashcards
Radiation consists of ____________ emitted from the nucleus of an unstable atom.
high energy particles (or waves)
There are three (main) types of radiation:
alpha (α) particles, beta (β−) particles, or gamma (γ) rays
Radiation is emitted ___________
randomly
This means that, although we understand why some nuclei emit radiation, it is impossible to predict exactly when a nucleus will emit radiation
Alpha (α) particles are
high energy particles made up of 2 protons and 2 neutrons (the same as a helium nucleus).
They are usually emitted from nuclei that are too large
Beta (β−) particles are
high energy electrons emitted from the nucleus (even though the nucleus does not normally contain any electrons)
They are usually emitted by nuclei that have too many neutrons
Gamma (γ) rays are
- high energy electromagnetic waves
- They are emitted by nuclei that need to lose some energy
- If these particles hit other atoms, they can knock out electrons, ionising the atom
When radiation passes close to atoms, it can knock out electrons, _________ the atom
Ionisation can cause chemical changes in materials, and can damage or kill living cells
ionising
Charateristics summarized
As the range and penetration increase, but the ionisation ____________
decreases
Because they have opposite charges, alpha and beta particles are deflected in ___________ directions
Beta is deflected by more than alpha, because beta particles have a much ___________ mass
Gamma is not deflected because gamma rays have___________
opposite,smaller,no charge
Alpha and Beta particles can also be deflected by magnetic fields. To find the direction of the deflection, we use ____________.
Flemings Left hand rule
Alpha is by far the most _________of radiation
Alpha particles leave a dense trail of ions behind them, affecting virtually every atom they meet
Because of this they quickly lose their energy and so have a _________ range
Their short range makes them relatively harmless if handled carefully, but they have the potential to be extremely dangerous if the alpha emitter enters the body
ionising form, short,
Beta particles are __________ ionising
The particles create a less dense trail of ions than alpha, and consequently have a ______ range
They tend to be more dangerous than alpha because they are able to travel further and penetrate the skin, and yet are still ionising enough to cause significant damage
moderately, Longer
Gamma is the ________ ionising form of radiation (although it is still dangerous)
Because Gamma rays don’t produce as many ions as alpha or beta, they are more penetrating and have a __________ range
This can make them hazardous in large amounts
Least, longer
Radioactive decay
is a random and spontaneous process in which an unstable nucleus will disintegrate into a more stable configuration by the emission of alpha-particles (helium nuclei), beta-particles (electrons) and/or gamma radiation (short-wavelength electromagnetic waves).