nuclear decay Flashcards
where did chemical elements come from
the big bang formed hydrogen, helium and lithium nuclei. 10,000 years later the universe cooled to allow electrons to be captured by protons. as the universe cooled, gas clouds formed, pulled by gravity. they became compressed and hot which triggered nuclear reactions
what do atoms do at high temperatures
they lose electrons to form plasma (ionised atoms and unbound electrons
what do nuclear reactions involve
the change in the nucleus of an atom. one element can change into another element
what are the two types of nuclear reaction
nuclear fission and nuclear fusion
what is nuclear fusion
lighter nuclei combine to form heavier nuclei
what 2 elements is the universe mainly made up of
hydrogen and helium
what conditions in the sun make nuclear fusion possible
high temperature
high pressure
what do the atoms need to overcome for the nuclei to fuse
the repulsion between the positive charges on the two nuclei. this needs high speed and large amount of kinetic energy
what do all stars turn hydrogen into
helium
with high temperature and high pressure what do heavy stars form
further nuclei reactions occur and they form heavier nuclei
what will the core contain after millions of years
helium, carbon, neon, sillicon and iron
how and when does the iron core explode
the iron core absorbs energy, when the core is mainly iron it explodes to form supernovae and disperses these elements into the universe
what is radioactivity
the nuclei of some atoms of a particular isotope are unstable and can break down forming new elements
the atoms that go through radioactive decay are called…
radioactive atoms
the isotopes of radioactive decay are called…
radioisotopes
