decay question

Started by xylashellx
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xylashellx

xylashellx

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hey guys i am having trouble understanding the answer to this question... here goes

A radioactive decay series begins with Uranium-238 and proceeds by emission of the following sequences of particles: alpha, beta, beta, alpha, alpha, and alpha. what is the atomic number of the final isotope formed at the end of the series?

Topscore says the answer is 84. Is that right? I thought that alpha changes the atomic number by -4 and beta changes it by +1 which would add up to -6 right? am i being stupid...please help thanks guys

kyle 🙂
 
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xylashellx said:
woops i meant to say that alpha changes the atomic number by -2. so 4*-2=-8
+2*(+1)=-6

thanks
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I would have answered the way you did too. I think they forgot about the Beta emissions. Beta can be -1 or +1 but according to what topscore gave us there's no room for our friend beta.
 
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ddsnp said:
I would have answered the way you did too. I think they forgot about the Beta emissions. Beta can be -1 or +1 but according to what topscore gave us there's no room for our friend beta.
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is that all the question says? cuz yea like dds, said beta can be -1 o1 +1... the only thing i can think of is if it underwent beta+ decay, then beta- decay, so it cancels out and nothing adds/subtracts.. so ur left with 92-8 = 84.

ANYONE ELSE??
 
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dentwannabe said:
is that all the question says? cuz yea like dds, said beta can be -1 o1 +1... the only thing i can think of is if it underwent beta+ decay, then beta- decay, so it cancels out and nothing adds/subtracts.. so ur left with 92-8 = 84.

ANYONE ELSE??
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Good point I think you are right it must have gone through beta positive then negative or vice versa!
 
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I copied this from the topscorepro.com website from the support area.

Version 07.20.02
1. Test 2, Chemistry, Question 69
Question stem is missing one additional "alpha".
 
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