41 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 ...
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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 ...
32 votes
Accepted

Why do all radioactive decay series terminate at lead?

There are four main decay chains for actinides and superheavy elements. This is a simple consequence of the fact that one of the main processes to increase a heavy nucleus' stability is the emission ...
30 votes
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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 ...
27 votes
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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 ...
23 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 &...
20 votes

Why do all radioactive decay series terminate at lead?

Short Answer: They don't. As the comments above indicate, the decay chains will terminate at a stable nuclei. For the series you mentioned in your question, lead has the first stable isotope. A ...
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 ...
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19 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 (...
16 votes
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If radium has such a long half-life, how can radon possibly be a threat to us?

There are two factors here: Radon is a gas and can thus enter the body very easily, through inhalation. $\ce{^222Rn}$ and its first 4 decay products are extremely radioactive, with halflives of ...
15 votes

Is lead radioactive?

One radioactive isotope of lead is $\ce{^{210}_{82}Pb}$, which has a half-life of 22.20 years. The only reaction that $\ce{^{210}_{82}Pb}$ undergoes is: $$\ce{^{210}_{82}Pb -> ^{210}_{83}Bi +^{0}_{-...
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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 ...
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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 ...
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13 votes
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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 ...
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13 votes
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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 ...
12 votes
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On the stability of deuterium

No, deuterium is completely stable. I found the answer at Hyperphysics, and it has to do with the mass energies of the products and reactants of this hypothetical reaction. The decay of deuterium ...
12 votes
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Why does technetium not exist in nature?

Technetium does occur in nature. From the Los Alamos page on technetium: Technetium was the first element to be produced artificially. Since its discovery, searches for the element in terrestrial ...
12 votes
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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 ...
11 votes
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Confusing Lines About Extinct Elements

Defintions Occur on Earth differentiates between all isotopes in the universe and isotopes which exist or have existed on Earth. The passage identifies that there are a total of 308 isotopes ...
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11 votes
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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 ...
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10 votes

Is lead radioactive?

As noted in the comments, the premise is wrong. Actually: Lead is the heaviest stable element. Why are heavier elements unstable? The atomic nucleus consists of neutrons and protons. Without ...
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10 votes
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Carbon dating: What to compare the new value against?

Large elements of my answer is drawn from my own notes that I use for teaching General Chemistry II. What is −0.693? Radioactive decay processes follow first-order kinetics. A first-order reaction ...
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10 votes
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How to find the average half life of radioactive nuclide which undergoes two different decays?

But I am getting the correct answer only if I take $\lambda_2$ as $2$ times the given decay constant for the second reaction. Is this because of $\underline{2}A$ on the reactant side instead of $A$? ...
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10 votes
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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 ...
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