P6.1 Flashcards
Describe 2 differences between the nuclear model of the atom and the plum pudding model of the atom. [4]
In nuclear model electrons orbit atom.In plum pudding model electrons are scattered throughout atom randomly.
In nuclear model +ve protons located in centre of atom in nucleus.In plum pudding model +ve mass spread out throughout atom.
Why can protons never move out of the nucleus
they are too tightly bound in the nucleus.
What are charged atoms called
Ions
What is an ion
Charges particle =
Different number of electrons
Outside nucleus.
What is an isotope
Isotopes are atoms of the same element containing a different number of neutrons.
What is a radioactive substance
one which contains unstable nuclei that become stable by emitting (nuclear) radiation.
What type of event is a radioactive event
RANDOM EVENT - can’t be predicted / influenced
What is alpha radiation
2 protons + 2 neutrons = helium NUCLEUS
What is beta radiation
A FAST moving electron
What is gamma radiation
High energy EM wave
Properties of alpha radiation
- Stopped by paper/skin
- Heavily ionising
- Slow
Properties of beta radiation
- Stopped by thin aluminium
- Moderately ionising
- Fast
Properties of gamma radiation
- Stopped by thick lead
- Lightly ionising
- Speed of light
Range of an alpha particle in air
A few cm
Range of a beta particle in air
1m in air
Range of a gamma wave in air
Unlimited range
Which types of these radiation are ionising
All 3 forms of nuclear radiation ionise substances/molecules/atoms they pass through.
Ionisation of living cells can damage/kill them.
CLASSIC GRADE 9 EXAM QUESTION“Explain why nuclear radiation is so dangerousto the human body” [4]
Nuclear radiation is highly ionising.
If the ions are created near/in the body, they will react with the cells of the body.
The cells become damaged.
Damaged cells continue to replicate, giving rise to a tumour.
What is ionisation
Ionisation is the process of turning a neutral atom/molecule into an ion
Which type of radiation is most dangerous outside of the body
Gamma = most dangerous because can penetrate the skin
Which type of radiation is least dangerous outside of the body
α = alpha = least dangerous because it can’t penetrate skin
Which type of radiation is most dangerous inside the body
α = most dangerous because it is heavily ionising