Download The nuclear stability graph

Nuclear stability graphs
 The graph of stable elements is
commonly referred to as the Band (or
Belt) of Stability. The graph consists of a
y-axis labelled neutrons, an x-axis
labelled protons, and a nuclei.
 Alpha α decay is located at the top of
the plotted line, because the alpha
decay decreases the mass number of
the element to keep the isotope stable.
 Beta β− decay accepts protons so it
changes the amount of protons and
neutrons. The number of protons
increase by 1 and the neutron number
decreases by 1.
 (Positron β+ decay, emission and
electron capture is when the isotope
gains more neutrons.)
 As with all decay pathways, if the
daughter nuclei are not on the Belt, then
subsequent decay pathways will occur
until they’re on the Belt
 Alpha decay occurs most often in massive nuclei that have too large a proton to neutron ratio
to remain stable.
 An alpha particle, with its two protons and two neutrons, is a very stable configuration of
particles.
 It is harder for large nuclei to hold particles together and as alpha particles are stable in
themselves the whole particle is more readily ejected from a weaker bound nucleus
The nuclear stability graph shows how many neutrons to protons need to be in an isotope’s
nucleus to be stable. It also shows what sort of decay occurs if an isotope is not stable.
a) What is the relationship between neutrons to protons for stable isotopes
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b) What type of decay is the most common with atomic number above 60?_______________
c) Why is this the case?
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