An observation about Technetium.

[jdurg]

Technetium, as we all know, is one of two elements with an atomic number less than 83 which is radioactive. (Promethium being the other). When looking around on the web, a lot of sites state that Technetium is highly radioactive and very dangerous. This is something that I kind of have to disagree with. I think that if someone were to obtain a sample of Tc-98, or perhaps it's Tc-99, it wouldn't really be all too dangerous. Here's my reasoning. Tc-98(99) is a beta emitter. It releases an electron when it undergoes decay as a neutron decomposes into a proton and an electron. The Technetium then becomes Ruthenium and the decay chain stops right there as the isotope of Ru it becomes is stable. Also, the particular isotope of Tc that I'm thinking of has a long half-life which means that it's radioactivity isn't fantastically high. Since the decay chain stops at the initial daughter product, all of the radioactivity would be coming from the Technetium itself. If you had a thick walled glass case, the glass and air should stop the beta emissions before it could escape the container. Therefore, why it Tc considered so bad? I'm thinking that it's just an attempt to stop people from trying to get ahold of it. The chemical toxicity may be fairly bad, but it's in the same column as manganese and rhenium, so I don't think it would be toxic like plutonium or uranium are. What are your thoughts on this?

[Gilded]

Of course, any extra radiation is "bad". Even with an isotope that has a stable daughter product, it's still radioactive. However, you must remember that even though technetium-98 goes through beta decay, when the nucleus is excited, gamma rays are released also. Even a relatively thick glass wall won't stop them. And when it comes to acquiring samples of radioactive isotopes, I say go nuts as long as

a) The isotope has a relatively long half-life (preferably over a million years). If the sample is very, very small, like some polonium on the tip of a needle, I'd say a couple of hundred years is enough

b) The isotope isn't too toxic, and if accidentally consumed goes right through your body (unlike for example Sr-90)

c) If it's atomic number is above 95, you don't want to have anything to do with it

[jdurg]

True, but all radioactive metals emit gamma rays.

[YT2095]

Americium doesn`t does it?

[Gilded]

If a nucleus is in excited state, it tries to lose the extra energy by releasing a gamma photon. Most cases, another particle(s) (such as an alpha-particle) is released ALSO. Although, if a nuclei is in metastable state (such as Tc-99m), it releases only the gamma photon to become more stable (but not necessarily stable as an isotope). I'm quite sure swansont could explain this with some fancy terms and so on, but now that he hasn't answered this I took the liberty of doing so.

[jdurg]

Americium is an intense gamma ray emitter. It is used as a portable Gamma Ray source.

 

I cannot think of any radioactive element that does not give off gamma rays. When the atom decays, the nucleus tends to wind up in an excited state. This excited nucleus has to get rid of its energy somehow, so it gives off a gamma ray.

[Gilded]

Trying to have alpha without gamma is like trying to have... err, corn flakes without corn.

[YT2095]

we are talking about the 241 isotope aren`t we?

[Gilded]

"we are talking about the 241 isotope aren`t we?"

 

Yeah, the one used in smoke detectors. Half-life about 430 years, decays through alpha emission (with a VERY minimal chance of spontaneous fission).

 

I'm starting to think swansont should have a word here, before I make a fool out of myself.

[swansont]

If a nucleus is in excited state, it tries to lose the extra energy by releasing a gamma photon. Most cases, another particle(s) (such as an alpha-particle) is released ALSO. Although, if a nuclei is in metastable state (such as Tc-99m), it releases only the gamma photon to become more stable (but not necessarily stable as an isotope). I'm quite sure swansont could explain this with some fancy terms and so on, but now that he hasn't answered this I took the liberty of doing so.

 

I have only intermittent access at the moment (and it's dialup )

 

I'm not a fan of "more stable" in describing an unstable nucleus - either it's stable or it's not. It can, however, become less unstable. Maybe just semantics, maybe not.

 

Many alpha decays don't emit gammas because the daughter is left in the ground state. Alpha decay is "ground state selective"

[swansont]

Technetium, as we all know, is one of two elements with an atomic number less than 83 which is radioactive. (Promethium being the other).

 

Actually there are 82. All elements have radioactive isotopes. Technetium and Promethium, however, have no stable isotopes.

[jdurg]

Actually there are 82. All elements have radioactive isotopes. Technetium and Promethium, however, have no stable isotopes.

 

 

Is anal-retentive spelled with a hyphen?

[cashsphere]

If you were even able to get ahold of technctium is it legal to own? Does anyone have any links on the legalities of owning certain elements?

[Gilded]

"If you were even able to get ahold of technctium is it legal to own? Does anyone have any links on the legalities of owning certain elements?"

 

In some cases the requiring a license part is defined by the amount of disintegrations per second. If you had a technetium radiation test source, with a couple of hundred disintegrations per second, I don't think anyone would take it away from you.

 

"Many alpha decays don't emit gammas because the daughter is left in the ground state. Alpha decay is 'ground state selective'"

 

Oh. Does this happen with other sorts of decays too?

[swansont]

"Many alpha decays don't emit gammas because the daughter is left in the ground state. Alpha decay is 'ground state selective'"

 

Oh. Does this happen with other sorts of decays too?

 

Generally no. Beta decays result in a "reshuffling" of the energy states and that usually leaves you in an excited state. Alpha decay can be modelled as a barrier tunneling problem, so it's the least tightly bound neutrons and protons that escape, and the reaction probability is highest when the alpha takes all the available energy.

[swansont]

Is anal-retentive spelled with a hyphen?

 

Scientists are generally of the attitude that they try to avoid any "you know what I meant" statements in technical discussions. Imprecision and ambiguity lead to confusion. While that may be good in e.g. politics, it's bad in science.

[ed84c]

was technetium formelly called tellurium, i couldnt find it on an old peridodic

[Gilded]

Tellurium is a totally different element. Technetium was called masurium, then named technetium (teknetos = Greek word for "artificial", since technetium was the first man-made element).

[ed84c]

ok thanks, is it technetium thats in mob fones and there is a civil war about in the congo

[Gilded]

Hmm? I'm not sure of Tc's all uses, but one is corrosion resistance. With technetium being radioactive and all that, it's used more in places where the radioactive doesn't concern humans too much (like a weather balloon or something like that). Technetium-99m on the other hand is probably the most famous or at least most used radioactive isotope in medical research.

 

And talking about uses of elements, it's always good to remember that just about every element straight from hydrogen to californium has a use of some sort.

[budullewraagh]

...californium being good for shredding peoples' flesh with neutrons?

[Gilded]

Come on now, don't discriminate good ol' californium. Cf-252 is used to inspect airline luggage for hidden explosives or detect moisture content in soil, for example. Just because a nucleus has an approx. 3% chance of undergoing spontaneous fission, doesn't make it less special than the other ones.