Particles and Radiation Flashcards
Define the A-Z nuclide notation
A = nucleon number (sum of p + n)
Z = atomic (proton) number
State the charge and mass of a proton.
Charge = 1.60e-19
Mass = 1.67e-27
How do you calculate the specific charge and what is its unit?
- specific charge = charge/mass
- unit = Ckg^-1
Note : charge = Z x 1.60e-19
mass = A x 1.67e-27
How many electrons are there in a neutral atom?
The number of electrons = the number of protons.
State the charge and mass of a neutron
Charge = o Mass = 1.67e-27
State the charge and mass of an electron.
Charge = -1.60e-19 Mass = 9.11e-31
What is an isotope?
A version of an atom with the same number of protons but different numbers of neutrons.
What characteristic of the atom does changing the number of neutrons affect?
The stability of the nucleus.
What is ionisation?
The removal (or addition) of electrons from (to) an atom or molecule.
How is isotopic data used?
Used to find the percentage of radioactive carbon-14 left in an object (organic matter).
So the approximate age can be calculated.
What is the attractive force responsible for holding the nucleus together?
The strong nuclear force.
What is the range of the strong nuclear force?
- 0.5-3.0 femtometres
- works equally between all nucleons
- at separations smaller than 0.5fm, the force is repulsive so nucleus doesn’t crush to a point
- falls rapidly towards zero after 3fm.
What kind of nuclei is alpha decay likely to happen and how does the nucleon and atomic numbers change?
- very large nuclei
- nucleon number decreases by 4
- atomic number decreases by 2
Why is the neutrino present in beta minus decays?
- Hypothesised as a neutral, almost zero mass
- carries away some energy and momentum (conservation of energy)
What happens to the nucleon and proton number in beta minus decay?
- the nucleon number stays the same
- the proton number increases by 1
- a beta minus particle and antineutrino are also emitted