44
votes
Is there radioactivity at absolute zero?
Theoretically, a radioactive material will still be radioactive at absolute zero, and its rate of decay will be $100.00\%$ of that at room temperature. Practically, at the lowest achievable ...
- 31.6k
39
votes
What happens to a radioactive carbon dioxide molecule when its carbon-14 atom decays?
An article by Snell and Pleasanton, 'The Atomic and Molecular Consequenses of Radioactive Decay', (J. Phys. Chem., 62 (11), pp 1377–1382, $1958$) supports Ben Norris's comment.
It is clear ... that ...
- 7,159
31
votes
Accepted
Why can radioactive contamination be spread by people?
Summary: there is not necessarily a contradiction between the two.
Radiation is not contagious, and
a person who has been exposed to ionizing radiation is not dangerous to other people once they are ...
- 3,284
28
votes
Accepted
Is it possible to speed up radioactive decay?
It is possible to modify nuclear decay rates using chemistry, though it is rare and the effect is usually very small. Here I summarize the information available in this link. You may want to see the ...
- 29.2k
25
votes
How toxic chemically is plutonium (Pu), neglecting the radioactive damage?
The toxicity is primarily due to radioactivity and to absorption by the body, where that radioactivity can act internally. There is, "significant deposition of plutonium in the liver and in the &...
- 35.3k
22
votes
How toxic chemically is plutonium (Pu), neglecting the radioactive damage?
Actual toxicity other than radioactivity is not, as far as I know, very well studied. Quite simply, most of the danger is the radioactivity in general, as well as the toxicity of decay products (...
19
votes
What is the benefit of using Am-241 in smoke detectors even though it is a radioactive element?
The usage in ionizing smoke detectors requires a radioactive isotope to work. In addition to a sufficient half-life to make a smoke detector with a suitable service life, Am-241 emits mostly alpha ...
- 62.5k
15
votes
Why does radiocarbon dating only work in nonliving creatures?
There are plenty of good sources online explaining the principle behind radiocarbon dating. For instance, the wikipedia explains:
During its life, a plant or animal is in equilibrium with its ...
- 22.9k
15
votes
How come nuclear waste is so radioactive when uranium is relatively stable with an extremely long half life?
The radioactivity associated with nuclear waste does not come from naturally occurring uranium, but from products associated with processing and using uranium. First off, uranium as it occurs in ...
- 62.5k
14
votes
Accepted
How come nuclear waste is so radioactive when uranium is relatively stable with an extremely long half life?
Radioactive isotopes (radionuclides to be more correct) are thermodynamically able to change into another nuclide, this decay has to be an exothermic event. For example if we consider beta decays for ...
- 5,277
13
votes
Accepted
Wouldn't radiolabelled phosphorus in DNA break it apart as it disintegrates?
Of course it would break, just like you said; also, a high-energy $\beta$ particle would kill quite a lot of bystander molecules. Also, if not for other reason, the resulting molecule would no longer ...
- 31.6k
12
votes
Accepted
How are organic compounds with radioactive atoms synthesized?
The current methods employed for synthesis fall into the following three categories1:
Chemical synthesis
Biochemical methods
Isotope exchange reactions
Chemical Synthesis:
Most chemical syntheses ...
- 6,338
11
votes
Why is Promethium the only radioactive Lanthanide?
Lanthanoids are not generally supposed to be radioactive, with exception of mentioned very long lived radioisotopes.
The longest half-life radioactive nuclides of lanthanoids ( in years )
$\ce{^{...
- 44.7k
11
votes
Accepted
If the half-life of an isotope exceeds the age of the Universe, then how is it measured?
Well, half-life describes the time after which half of the substance has decayed.
This is all probability and statistics. If you look at a single atom you cannot make any prediction when it will ...
- 5,802
11
votes
Why is the only natural source of radium compounds uranium minerals?
You can't find primordial radium because it's half life is too small compared to earths age.
Even the radium isotope with the longest half life, $\ce{^{226}Ra}$ has a half life of only 1600 years ...
- 3,161
10
votes
Accepted
Radioactivity of materials
No. Radioactivity means that the nucleus of a particular atom is unstable, and the nucleus will decay to a more stable state either by decomposing or emitting energy (as a photon). This instability ...
- 13.2k
10
votes
Why can radioactive contamination be spread by people?
Radiation isn't "contagious" unless you are heavily contaminated and can cause damage to others
The firefighters in Chernobyl attended the fire before anyone fully appreciated just how bad ...
- 37.8k
10
votes
Elements with most commonly occurring isotope being different from the most stable one
Yes.
You're probably thinking about comparing nuclear stability by comparing radioactive decay half-lives, which is a reasonable and intuitive (though somewhat limited) criterion. Already here there ...
- 29.2k
9
votes
Half-Life of Radioactive Isotopes: Why? How?
After the half-life time, half of the atoms you initially had are still there good as new, the others have split off an alpha particle, undergone beta decay, and might even have decayed further.
Sit ...
- 12.3k
9
votes
How are Uranium and such materials made
Some radioactive materials are made by man, others have been parts of earth's rocks since they were formed
Radioactive materials are not all the same. some are man-made and some have been with us ...
- 37.8k
9
votes
Kinetics of a simultaneous parallel radioactive decay
The question has already been solved by Yashwini and the answer given is correct.$^2$ A more intuitive and specific to question explanation would follow here.
Now, the two reactions given are:
\begin{...
9
votes
Why is tellurium-128 so stable compared to the other radioisotopes?
Tellurium-128 is in no way extraordinary or unique.
Cape Chelyuskin in Russia is the northernmost extreme point of continental Eurasia. Tellurium-128 is not an extreme point of anything. There are ...
- 31.6k
9
votes
Accepted
How do alpha particles contribute to pressure of nuclear decay products?
When it is an alpha particle, it is not a molecule(IUPAC), that is by definition neutral.
An electrically neutral entity consisting of more than one atom (n>1). Rigorously, a molecule, in which n&...
- 44.7k
8
votes
Is there radioactivity at absolute zero?
Yes, it will continue to be radioactive. This is because the instability of the nucleus is due to the balance of forces internal to it, not to the motion of it as a whole object. It's just like how ...
- 338
8
votes
Why does radiocarbon dating only work in nonliving creatures?
The metabolism of living creatures keeps the dynamic equilibrium of their $\ce{^{14}C/^{12}C}$ ratio with the enviromental $\ce{^{14}C/^{12}C}$ ratio via photosynthesis, breath, food and excrements.
...
- 44.7k
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