Odd One Out

[Bluebell]

I know any 11 year old could answer this, and I apologise for being so thick!
Which is the Odd One Out from the following....and Why?
Hydrogen, Helium, Radium, Lithium, Beryllium
Thank you.

[OBonio]

I'm going to say Helim as it is inert. The only Nobel gas mentioned.

[OBonio]

Helium, even!

[Gef]

Noble, even!

[Bluebell]

Thank you for your help. Much appreciated!

[SarCaustic]

I'd have picked Radium, because all the others are in order of atomic mass i.e. they are the first 4 elements in the periodic table.

[gen2]

Radium is also the only radio-active element in the choices

Hydrogen is the only one with no neutrons in its nucleus

[Bluebell]

And I thought it was all going to be so easy to make a choice!!! I'm going with all the suggestions given and the quizmaster can take his pick. For a possible �5 book token, this is hard work! Thank you though, for all for your suggestions.

[THECORBYLOON]

Radium comes fae the Latin word "radius", meaning "ray" but the other names are of Greek origin. Can you not put in two entries under differnt names?

[mibn2cweus]

Hydrogen is the only one not ending with "ium" . . .

[Bluebell]

I'm going with all the options. This question is too general to be able to come up with the only correct answer. It'll be interesting to see what the quizmaster gives as his interpretation when he publishes the answer. Thank you once again for all your help. Have a good Easter!

[stewey]

Also, beryllium could be the odd one out because it contains four syllables whereas the rest contain three.

[stewey]

Bluebell, all of these answers should demonstrate to your quizmaster that it is extremely difficult to pose an "odd man out" question that has only one "correct" answer. Most teachers or instructors (if that is what he/she is) avoid those types of questions on exams or tests. If it's just for fun, then ok.