How to identify Unknown element?

[CuriousOnes]

Okay, this is a simple question, but the context is a bit unconventional.  There is a claim from a man named Bob Lazar that he was hired by the government in the 80's to help reverse engineer a UFO.  He claims that the fuel used by the UFO(s) was a stable isotope of Element 115, AKA Moscovium.  

Obviously there is a lot of unpack there about the veracity of the claim and we could easily get off track.  What I want to know is how you would know what it was you had in your hand.  For the sake of argument, let's assume that a materials scientist had a stable isotope of element 115 about the size of a ping pong ball.  I could be wrong, but I don't think spectroscopy would be of use here since there has never been anything to base the results off of.  You could do a spectroscopic analysis, but the results wouldn't match any known element.

It would assumedly be very dense and heavy, but that really does no good in identification.  Could a chemist predict how it would react with other chemicals and break it down into other periodic elements?

[swansont]

!

Moderator Note

To all: Please note that the discussion here will not focus on Lazar or his claims. If it helps, simply substitute "unknown stable element" as the target

 

 

Yes, your spectroscopy would yield an unknown (previously unobserved) spectrum.

You could pop a sample into a mass spectrometer and get the atomic mass. You could try to fully ionize it to get the atomic number. If you can make it into a hydrogen-like state (i.e. one electron), the spectroscopy would be easy to predict and compare.

There is also Moseley's law, which predicts the x-ray spectrum

https://protonstalk.com/physics/moseleys-law/

You could bombard it with some energetic particle (e.g. neutrons or protons) and look at the particles produced.

[CuriousOnes]

Thank you!  I consider myself somewhat scientifically literate, but this question had been bugging me for sometime.  

Skimmed over Moseley's law too.  Was completely ignorant of it.

[exchemist]

1 hour ago, CuriousOnes said:

Okay, this is a simple question, but the context is a bit unconventional.  There is a claim from a man named Bob Lazar that he was hired by the government in the 80's to help reverse engineer a UFO.  He claims that the fuel used by the UFO(s) was a stable isotope of Element 115, AKA Moscovium.  

Obviously there is a lot of unpack there about the veracity of the claim and we could easily get off track.  What I want to know is how you would know what it was you had in your hand.  For the sake of argument, let's assume that a materials scientist had a stable isotope of element 115 about the size of a ping pong ball.  I could be wrong, but I don't think spectroscopy would be of use here since there has never been anything to base the results off of.  You could do a spectroscopic analysis, but the results wouldn't match any known element.

It would assumedly be very dense and heavy, but that really does no good in identification.  Could a chemist predict how it would react with other chemicals and break it down into other periodic elements?

In principle it should have some chemical properties in common with bismuth, though modified by the relativistic effects that influence orbital stability in very heavy elements, so may resemble thallium in some respects. There is a write up of expected chemical properties in the Wiki article on this element.

But of course, if it were stable, we would already know it was not Moscovium.😉