Odd one out

[halcyon days]

Can anyone tell me which is the odd one out of these please

Brass/Pewter/steel/polonium/bronze

[theprof]

Well , to start with there are four alloys in your list whilst the fifth is the only element.
On the other hand, four of the list are non-radioactive whilst the fifth is radioactive.
The same element is the odd one out in both cases. Can you find it now?

[halcyon days]

Thank you. Got it now from your excellent spoon fed clues.

[factor-fiction]

I'm sure you've got the right answer but just to clarify in case anyone is thinking "eh, didn't know bronze was radioactive", when theprof refers to "the fifth" he doesn't mean the 5th in the list). The answer is Polonium.

[theprof]

Hmm, full marks for your observation factor30. That's exactly the reason why I said "four OF the list"!

Yes, you're right the answer is Polonium. I provided two rather obvious reasons why Polonium is the "odd one out". However, the reality is that are are quite a few other reasons why Polonium is the answer. I'm aware of them but I wonder if others can spot them?

[squarebear]

It's the only one that ends with the letter M ;-)

[chakka35]

Here's one:
The elements that make up the four alloys all occur in the human body. Polonium does not.