Atomic Structure-Paper 1 Flashcards
What is the approximate radius of an atom
1x10^-10 meters
How big is an atom compared to its nucleus
Atom is 10,000 times bigger than a nucleus
What is radioactive decay
When an unstable nucleus decays ticking out nuclear radiation
What is half life
The average time is taken for half of the radioactive nuclei to decay
What are the 4 types of nuclear radiation
Alpha
Beta
Gamma
Neutrons
What is ionising power
The ability to remove electrons
What is penetrative power
The ability to travel through a material
Describe an alpha particle
2 proton 2 neutrons
Helium
Describe the Beta particle
High speed electron emitted from the nucleus
Describe gamma radiation
An electromagnetic wave
What is activity
The rate at which a source of unstable nuclei decays
Unit is Becquerel
What is count rate
The number of decays recorded each second by a detector
What happens in alpha decay
Two protons and neutrons lost from the nucleus
Emitted as an alpha particle
Mass num decrease by 4 and Atomic number decreased by 2
New element formed
What happens in beta decay
Neutron decays into a proton and an electron
Electron is emitted from the nucleus
Mass num stays the same atomic number increase by 1
New element is formed
What happens in gamma decay
Electromagnetic wave is emitted from nucleus
Mass number stays the same
Atomic num stays the same
What is radioactive contamination
The unwanted presence of materials containing radioactive atoms on other materials
What is irradiation
The process of exposing an object to ionising radiation
This does not become radioactive
What is Bohr contribution to the nuclear model
Suggesting adding electrons orbiting tjr nucleus
Describe James Chadwick contribution to the nuclear model
Discovered the neutron through a scattering experiment
Despite the process of nuclear fission
When an unstable nuclei absorbs a neutron to produce 2 smaller nuclei
Emitting 2 or 3 neutrons and game days and energy
Neutrons produced collide with another
Causing a chain reaction
How does a nuclear power station generate electricity
Energy is used to heat the water which produces stream which turns the turbine which turns the generator which generates electricity
Describe the process of nuclear fusion
When two small nuclei fuse to form a heavier nucleus releasing energy
Explain how the chain reaction in a nuclear power station is controlled
Boron control rods are used to absorb excess neutrons which slows down the chain reaction
Explain how the efficacy of a nucleus power station can be increased
A moderator is used to slow down the neutrons to increase interaction with the unstable nucleus
