= Sulfur-32
{title2=$^{32}\mathrm S$}
<Sulfur-32> is a stable <isotope> of <sulfur> whose <atomic nucleus> contains 16 <protons> and 16 <neutrons>. Its <mass number> is $32$, the sum of those counts. The measured relative <atomic mass> is approximately $31.9720711744$; a <mass number> is an integer count, whereas a relative <atomic mass> is a mass ratio.<Atomic Weights and Isotopic Compositions for All Elements by National Institute of Standards and Technology>[Sulfur row: mass 32, relative atomic mass and isotopic composition]{ref}
The same NIST table gives a representative <isotopic abundance> of $0.9499$, or $94.99\%$, making <sulfur-32> the predominant natural sulfur isotope. This is a representative composition, not an immutable percentage in every sample. Using the listed <sulfur-34> fraction $0.0425$, the corresponding isotope ratio is $0.0425/0.9499\approx0.04474$: about 4.47 <sulfur-34> <atoms> per 100 <sulfur-32> <atoms>.<Atomic Weights and Isotopic Compositions for All Elements by National Institute of Standards and Technology>[Sulfur isotope rows 32–36]{ref} An isotope ratio and a percentage of all sulfur atoms have different denominators.
<Sulfur-32> is also the daughter of <phosphorus-32> <beta-minus decay>. One nuclear <neutron> becomes a <proton>, changing $Z=15$ to $Z=16$ while retaining <mass number> $32$.<Phosphorus-32 in LNE-LNHB Table de Radionucleides>[Page 1, decay scheme]{ref} This connects a radioactive tracer to a stable daughter without turning their chemical identities into the same thing.
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