2.7 - Types of radiation Flashcards
What do all forms of the same element have in common?
The number of protons
What is the name given to the number of protons in an atom?
Atomic number
Proton number
What is an atom’s mass number (Nucleon number)?
The total number of protons and neutrons in the atom
What is an isotope of an atom?
An atom of the same element that has a different number of neutrons (so a different mass number), but the same number of protons
What are the properties of the following 3 sub-atomic particles with respect to relative mass and relative charge:
Proton
Neutron
Electron
Proton:
Mass: 1
Charge: +1
Neutron:
Mass: 1
Charge: 0
Electron:
Mass: almost 0
Charge: -1
The number of electrons in an atom is always the same as the number of _____, so atoms are electrically neutral overall. Atoms can lose or gain _____. When they do, they form charged particles called ions:
protons
electrons
Why are atoms radioactive?
There is an imbalance between the numbers of protos and neutrons which makes it unstable
Why do unstable nuclei give out radiation?
Unstable nuclei undergo decay to become more stable.
As they release radiation their stability increases
What is the name of the process in which an unstable nucleus gives out radiation to become stable?
Radioactive decay
State the 3 main types of ionising radiation emitted from the unstable nuclei of radioactive atoms?
Alpha, beta and gamma radiation.
What does an alpha particle consists of?
Two protons and two neutrons
It is the same as a helium nucleus
What will stop alpha radiation from passing through a point?
A few cm of air, skin or a thin sheet of paper
What is the ionising power of an alpha particle?
Very high - most damaging inside the body
What does an beta particle consist of?
High-energy electrons emitted from the nucleus.
What will stop beta radiation from passing through a point?
A thin sheet of aluminium
Several metres of air
What is a gamma ray?
High energy electromagnetic wave
What will stop gamma radiation from passing through a point?
Several cm’s of lead
A few metres of concreate
Which type of radiation is most ionising?
Alpha radiation
Which type of radiation is least ionising?
Gamma radiation
Which type of radiation is least penetrating?
Alpha radiation
Which type of radiation is most penetrating?
Gamma radiation
State any changes to mass or charge that occur due to the emission of a gamma ray.
Both mass and charge remain uncharged
State any changes to mass or charge that occur due to the emission of a beta particle.
Mass remains unchanged, charge increases by 1
State any changes to mass or charge that occur due to the emission of an alpha particle.
Mass decreases by 4 and charge decreases by 2
Describe the nature of radioactive decay.
Random
Which nuclei decays and when is determined only by chance
It is impossible to predict which nuclei will decay and when
State two techniques that can be used when carrying out experimental work, to combat the random nature of decay
- Take repeat-readings
2. Carry the experiment out over a long period of time
Why is radioactive waste such a problem?
It remains radioactive for thousands of years
It can cause harm to living cells so must be stored appropriately
How is nuclear waste disposed of?
1) cooled in large water tanks
2) Then turned into a type of glass so it can’t flow
3) Then placed inside a steel drum and sealed in concreate
4) Then buried deep underground
Most background radiation coms from natural sources. Give some examples.
- Radon
- Cosmic rays from space
- Rocks
- Food and buildings
Some background radiation comes from artificial sources. Give some examples.
- Nuclear industry (nuclear weapon testing, nuclear accidents)
- Medical industry (X-rays)
What is half life?
The time taken for the number of nuclei of the isotope in a sample to halve
Alpha decay:
Two protons and two neutrons are lost from a nucleus when it emits an alpha particle. This means that:
the atomic mass number decreases by _
the atomic number decreases by _
A new element is formed that is two places to the left in the periodic table than the original element.
4
2
In beta decay, a neutron changes into a ____ plus an _____. The proton stays in the nucleus. The electron leaves the atom with high energy as a beta particle.
The nucleus has one more proton and one less neutron when it emits a beta particle. This means that:
the atomic mass number stays the same
the atomic number increases by 1
proton
electron
