Atomic Structure And Radioactivity Flashcards
What is radioactive decay?
Some isotopes have unstable nuclei and to become stable the nucleus gives out radiation. It is completely random process
What is an isotope?
An element that has different numbers of neutrons to the original.
What is the “activity” in terms of decay
the rate at which a source of unstable nuclei decay.
what is the units for activity/ nuclei decay
Becquerel (Bq)
1 Bq = 1 decay per second
What piece of equipment is used to measure the activity of a radioactive source?
Geiger - Muller tube
What is count rate in terms of decay?
The number of decays recorded each second by a detector
What is the alpha particle structure
2 protons and 2 neutron
Aka the same as the nucleus of a helium atom
What is the structure of a beta particle?
1 electron
What is a beta particle?
An electron which is ejected from a nucleus at a very high speed.
How is a beta particle formed
When a neutron changes into a proton and electron and the electron is ejected
Is a gamma ray a particle?
NO
Which type of radiation is a type of electromagnetic radiation from the nucleus
Gamma Rays
Alpha particle range in air
Alpha particles are large and can travel 5 cm in the air before stopping as they collide with the air particles
Beta particles range in air?
Can travel around 15cm before stopping
Gamma radiation range in air
Can travel a couple of metres before stopping
What is the barrier that stops alpha particles and what does this mean about their penetrating power?
A single piece of paper
Alpha particles have weak penetrating power
What barrier can stop beta particles and what does this mean about their penetrating forces?
A few centimetres of aluminium
This means it has stronger penetrating forces
What is the barrier that can stop gamma radiation and what does this mean about its penetrating power?
Several centimetres of lead
Has very strong penetrating power
What is a ionising power?
When radiation collides with atoms, that can cause the atoms to lose electrons from ions
What are the three radiations ionising power?
Alpha - very strong
Beta - quite strong
Gamma - weak
What are the two examples of large unstable nuclei?
Plutonium + Uranium (certain isotopes)
What happens in nuclear fission
A large and unstable nucleus splits
Can happen spontaneously but quite rare
normally for fission to take place the nucleus has to absorb a neutron. This causes the element to split and form two smaller nuclei (daughter) which are mostly even in size. It also emits 2 or 3 neutrons and gamma radiation. The neutrons that are released can create more fission after wards. This releases lots of energy.
What type of energy do all fission reaction products have?
Kinetic energy
What type of reaction is a cycle of fission
Chain reaction
