Radioactivity (10) Flashcards
At the centre of every atom is a _____________
Nucleus
The nucleus of an atom, contains __________ and ___________
Protons and neutrons
The nucleus of an atom makes up most of the _______ of the atom, but takes up virtually no __________
Weight Space
The electrons are _______________ charged and are really small
Negatively
The number of protons in the nucleus is called the ____________ number
Number of protons = atomic number
The total number of protons and neutrons in the nucleus is called the __________ number
Mass
What are isotopes
Atoms of the same element with different numbers of neutrons
Isotopes are atoms of the same __________ with different numbers of ___________
Element
Neutrons
This means that different isotopes have different __________ numbers
Mass numbers
Usually each element only has one or two ___________ isotopes
Stable
If the nucleus of an atom is unstable then it tends to be _____________. The unstable nucleus decays and emits _______________
Radioactive
Radiation
Radioactive decay is a ____________ process
Random
The nuclei of unstable isotopes break down at ___________. If you have 1000 unstable nuclei, you can’t say when any of one them is going to decay, and you can’t do anything at all to make a _________ happen
Random
Decay
Each nucleus decays spontaneously and is completely unaffected by physical conditions such as _________________ or ____________ bonding
Temperature
Chemical bonding
When a nucleus does decay it spits out one or more of the three types of radiation _________, ________ or __________
Alpha
Beta
Gamma
In the process of decay, the _________ often changes into a new element
Nucleus
There is (low level) background nuclear radiation all around us all the time which come from
Space
Substances on earth
Living things
Human activity (nuclear explosions)
Nuclear radiation causes ______________ by bashing into atoms and knocking _____________ off them. Atoms (with no overall _________) are turned into ______ (which are __________) - hence the term ionisation (being turned into ions)
Ionisation
Electrons
Charge
Ions
Charged
The further the radiation can penetrate before hitting an atom and getting stopped the _________ damage it will do along the way and so t?’‘he _________ ionising it is
Less Less
____________ radiation can be detected with a Geiger-Muller detector
Ionising
Alpha particles are made up of ___ protons and ___ neutrons
2 protons and 2 neutrons
What are the features of an alpha particle
Big, heavy, slow moving
What are the features of a beta particle
Quite fast, quite small
What are the features of a gamma particle
No mass - just energy
___________ are big and heavy so they don’t _______________ far into materials and are stopped quickly
Alpha
Penetrate
Because of their size, alpha particles are strongly ______________ which means they bash into a lot atoms and knock ______________ off them before they slow down, which creates lots of _______
Ionising
Electrons
Ions
Because they’re electrically charged, ________ particles are deflected by electric and ____________ fields
Alpha
Magnetic
How does emitting an alpha particle change the mass and atomic numbers of an atom
The mass number decreases by 4 and the atomic number decreases by 2.
A beta particle is an ____________ which has been emitted from the nucleus of an atom when a __________ turns into a proton and an electron
Electron
Neutron
When a beta particle is emitted, the number of ___________ increases by 1. So the __________ number increases by 1 but the _______ number stays the same because a neutrons is lost when it turns to a proton. (The mass number stays the same because the neutron is replaced by a proton). (E.g. instead of their being 6 protons and 6 neutrons, there are now 7 protons and 5 neutrons - still 12 overall but proton number is higher)
Protons
Atomic
Mass
Beta particles penetrate moderately before colliding and are moderately ________________ too
Ionising
Because beta particles are (negatively) ___________ they are deflected by electric and magnetic fields
Charged
___________ particles can penetrate a long way into materials without being stopped
Gamma
Gamma rays are ___________ ionising because they tend to pass through rather than collide with _________. But eventually they hit something and do damage
Weakly
Atoms