Topic 3: Atomic structure Flashcards
what are the masses and charges of protons, neutrons and electrons?
protons: mass: 1, charge: 1+
neutrons: mass: 1, charge: 0
electrons: mass: 2/1000, charge: -1
what was JJ Thomsons discovery on the atom?
plum pudding model - ball of positive charge with electrons embedded into it
what was Dalton’s discovery on the history of the atom?
tiny spheres
what was Rutherfords discovery on the atom?
alpha particle experiment
- some alpha particles went straight through - there’s empty space
- some deflected - centre is positive
- some bounced back - centre is dense
discovered the proton
what was Bohr discovery on the atom?
discovered electrons were found on shells (not a sea of electrons)
what was Chadwick discovery on the atom?
discovered neutrons
describe what alpha radiation is, it’s penetration power, the ionisation power and what it’s used for
- alpha is 2 neutrons and 2 protons, nucleus ejects helium nuclei (has a mass of 4 and a charge of +2)
- it’s low penetrating (can be stopped by air, skin, paper)
- high ionisation
- used for smoke alarms
describe what beta radiation is, it’s penetration power, the ionisation power and what it’s used for
- beta is fast moving electron (mass nearly 0, charge -1), neutron turns into a proton and electron is ejected from the nucleus
- moderately penetrating (stopped by thin sheet of aluminium)
- moderately ionising
- used for paper mills/ controlling the thickness of paper
describe what gamma radiation is, it’s penetration power, the ionisation power and what it’s used for
- gamma is EM waves, high frequency/ short wavelength (mass is 0 and charge is 0)
- it’s high penetrating (can penetrate through the skin)
- low ionising
- sterilising surgical equipment, gamma knife - kills cancerous cells, used to detect leaks in pipes
what is fission?
breaking large nuclei into smaller nuclei
where does fission occur?
nuclear power stations
what is the process of fusion
the joining of light nuclei (hydrogen) to form a heavier nucleus
produces large amounts of energy
no nuclear waste
has not been done earth - don’t get high enough temperature/ pressure
what is half life?
the time it takes for half of the nuclei to decay and become stable
what is needed for the use of alpha/ beta and gamma?
- half life:
body - short half life (relatively short) - type of radiation emitted:
- ionisation power
- penetration