fission ect. Flashcards
Fission may cause
a chain reaction
what is present at the end of fusion
a larger nucleus
what is present at the start of fusion
two lighter nuclei
how does the total mass change before and after in fusion
total mass before is larger than total mass after
explain how the process of nuclear fusion leads to the release of what?
lighter nuclei join to form heavier nucleus and some of the mass is wasted to energy of radiation
what does radioactive mean
a sample containing unstable nuclei which gives out radiation
how can one alpha particle be represented (symbol)
4
a
2
how can one alpha particle be represented (using helium)
4
He
2
how can one beta particle be represented (symbol)
0
B
-1
how can one beta particle be represented
(using electron)
0
e
-1
Radioactive decay is _______
random
what is the half-life of a radioactive isotope
the time it takes for the number of nuclei of the isotope in a sample to halve
the half life _____________ as more and more of the nuclei decay
stays the same
the first model of an atom was designed by who?
john Dalton
the first model was theorised to be what?
a solid sphere
carbon-13 and carbon-12 are isotopes the of the same element. what does this mean?
they contain the same number of protons but different number of neutrons
what is a beta particle?
a high speed electron
what is an alpha particle?
2 neutrons
2 protons
what is a gamma ‘particle’?
electromagnetic radiation
what cannot alpha particles penetrate
paper
what cannot beta particles penetrate
thin sheet of aluminium foil
what cannot gamma particles penetrate
thick lead or concrete
In order for unstable nuclei to become stable it needs to
emit radiation
why are atomic nuclei unstable
too many nucleons (neutrons and protons)
which radiation is most ionising
Alpha particles
natural background sources include
rocks and cosmic rays from space
manmade background sources include
fallout from nuclear weapons testing,
nuclear accidents
