[Abder-Rahman]

If we know that the "Monoatomic ion" is an ion formed of one atom, the if we have the compound "MgO", we say that Mg2+ (2 is charge number) is an monoatomic ion, and O2- (2 is charge number) is also a monoatomic ion.

If we have this compound for example: NaO2 (2 is subscript), do we say that Na+ is a monoatomic ion? And, what do we call O2 in this case?

So, for a monoatomic ion to be monoatomic we must NOT have more than one atom? Does it go like that?

Thanks.

[rabolisk]

You would never have NaO₂. A monatomic ion is simply an ion that only consists of one element.

[Abder-Rahman]

You would never have NaO₂. A monatomic ion is simply an ion that only consists of one element.

I think we can have NaO2, as it is a peroxide.

But, my question was specifically about "Monoatomic ions".

[rabolisk]

I think you can have sodium peroxide too, Na₂O₂, that is.

If your question is whether something like a peroxide, O₂^2-, which consists of two atoms but one element is a monatomic ion... I've seen both definitions.

[Borek]

http://en.wikipedia.org/wiki/Sodium_superoxide

[Abder-Rahman]

I think you can have sodium peroxide too, Na₂O₂, that is.

If your question is whether something like a peroxide, O₂^2-, which consists of two atoms but one element is a monatomic ion... I've seen both definitions.

Thanks for your reply. So, do you think  O₂^2- is a monoatomic? Or it isn't snce it contradicts the definition?

[Catsceo]

I think you can have sodium peroxide too, Na₂O₂, that is.

If your question is whether something like a peroxide, O₂^2-, which consists of two atoms but one element is a monatomic ion... I've seen both definitions.

Thanks for your reply. So, do you think  O₂^2- is a monoatomic? Or it isn't snce it contradicts the definition?

If you go my the definition that monoatomic means 1 atom, O₂ implies that the ion contains 2 atoms, so polyatomic.  If you go by the element, then I suppose its monoatomic.  The 1st one makes more sense to me.

[Abder-Rahman]

You would never have NaO₂. A monatomic ion is simply an ion that only consists of one element.

I think we can have NaO2, as it is a peroxide.

But, my question was specifically about "Monoatomic ions".

It seems it is a "Sodium superoxide". See the wikipedia link in @Borek post.