radioactivity Flashcards
what’s radioactivity?
Some atoms are unstable. They break down and release radiation to become stable.
What is a half-life
The time taken for half of the radioactive nuclei in a sample to decay.
Types of Radiation
Non-Ionising Radiation (safe in small amounts)
Example: Light, radio waves, microwaves.
Ionising Radiation (can be harmful)
Example: Alpha, Beta, and Gamma radiation from radioactive materials.
e.g of radiation
Alpha Radiation (α)
Beta Radiation (β)
Gamma Radiation (γ)
what’s alpha radiation stopped by?
alpha radiation is stopped by paper or skin
what’s Beta Radiation (β) stopped by?
Beta radiation is Stopped by aluminium.
Gamma Radiation (γ)
Gamma radiation is Stopped by thick lead or concrete.
what alpha radiation?
A helium nucleus (2 protons, 2 neutrons)
what’s beta radiation?
A fast-moving electron.
what’s gamma radiation?
A wave of energy. is a type of electromagnetic wave (like X-rays but stronger) released from unstable atoms.
types of radiation
alpha beta gamma
symbol for alpha
α
symbol for beta
β
symbol for gamma
γ
dangers of alpha radiation
Dangerous if inhaled or ingested (can cause lung cancer), but not harmful outside the body.
dangers of beta adiation
More dangerous than alpha radiation if it enters the body because it can penetrate deeper into tissues.
dangers of gamma radiation
Dangerous in large doses because it can penetrate deep into tissues and organs, but less ionising compared to alpha and beta.
speed of gamma radiation
The speed of light (fastest of all radiation types).
Penetration of gamma radiation
Very high; can go through paper, aluminium, and even thick lead or concrete.
Ionising power of gamma radiation
Weak; causes less damage compared to alpha and beta.
uses of beta radiation
medical tracers, and some types of radiation therapy.
speed of beta radiation
Faster than alpha radiation.
Ionisation power of beta radiation
Moderate; it can cause damage but not as much as alpha radiation.
Penetration of beta radiation
Medium; stopped by aluminium (around 5 mm thick).
charge of beta radiation
Charge: -1 (negative for electrons) or +1 (positive for positrons).
charge of a alpha radiation
+2.
charge of gamma radiation
no charge. it’s neutral
what does gamma radiation consist of?
gamma rays
charge of alpha radiation
+2 (positive).
penetration of alpha radiation
Very weak; stopped by paper or skin.
penetration of gamma radiation
Very high; can go through paper, aluminium, and even thick lead or concrete
speed of alpha radiation
low-moving compared to beta and gamma.
speed of gamma radiation
Faster than alpha radiation.
Uses of Radiation
Medical: X-rays, cancer treatment (gamma radiation), and sterilisation of medical tools (gamma radiation).
Industrial: Carbon dating (carbon-14), smoke detectors (americium-241), food sterilisation.
Tracers: Radioactive isotopes are used in medical imaging (e.g., gamma tracers in PET scans).
Safety Precautions
Shielding: Use materials like lead or concrete to stop gamma radiation, and paper or aluminium for alpha and beta.
Distance: The further you are from a radioactive source, the less exposure.
Time: Minimising the amount of time spent near a source of radiation reduces risk.
Contamination
When radioactive material is inside or on the body.
Irradiation
When you’re exposed to radiation but not directly contaminated.
what’s Nuclear Fission
Nuclear fission is the process where the nucleus of an atom splits, releasing a large amount of energy (used in nuclear power stations).
Isotopes
Atoms of the same element with same numbers of protons and electrons but different numbers of neutrons.
Radiation
Energy emitted in the form of particles or electromagnetic waves.
Ionisation
The process where atoms or molecules gain or lose electrons, which can cause cell damage.
Decay Equation
Parentisotope→Daughterisotope+Radiationemitted
what’s an isotope?
Atoms of the same element with same number of protons and electrons but different numbers of neutrons.
Radiation
Energy emitted in the form of particles or electromagnetic waves.
Ionisation
The process where atoms or molecules gain or lose electrons, which can cause cell damage.
what’s half life
Half-life is the time it takes for half of a radioactive substance to decay (break down into a more stable form).
what’s radioactive decay?
radioactive decay is when an unstable nucleus becomes stable by loosing some subatomic particles.
3 types of radioactive decay
Alpha α decay
Beta(β-) decay
Beta(β+) decay
what happens during decay
During decay, the atom gives off energy in the form of radiation (like alpha, beta, or gamma radiation).
how many protons and neutron does a alpha radiation have
He 2 protons and 2 neutrons
what happens when an atom looses alpha particle
the mass number decrease by 4 and the atomic number decreases by 2
what happens when an isotope has too many neutrons?
it decays by beta- decay
how do u solve beta equation
-1 the mass number
how do u solve a beta + equation
mass number stays the same but the atomic number increase by 1
how do u solve alpha equation
the mass numb decrease by 4 and the atomic number decreases by 2
what’s condensation
(Gas → Liquid)
how does condensation happen?
When a gas is cooled, the particles lose energy, slow down, and come together to form a liquid. This change is called condensation.
Example: Water vapor in the air turning into droplets of water on a cold surface.
what’s Sublimation
(Solid → Gas)
how does sublimation happen
Some substances can change directly from a solid to a gas without passing through the liquid state. This is called sublimation.
Example: Dry ice (solid CO₂) turning directly into carbon dioxide gas.
