Which is an example of a polyatomic ion? a)h2b)co3-c)mg+d)ne+ -

CO3- would be the polyatomic ion.  poly means many.  the other options are single-atom ions

Explanation:

To answer this quetion it is important to know that:

- An ion is a particle with positive or negative charge. If it has positive charge is called "cation" and if it has negative charge is called "anion". The charge of an ion it is represented by plus symbol (+) or minus symbol (-).  

- Polyatomic means that there are more than one atom.

Let see the options:

H₂ has two hydrogen atoms so it is polyatomic (and also a molecule), but it is neutral because it has no positive or negative charge.CO₃⁻ it is not exactly the correct form, the correct form it is CO₃⁻² and this is polyatomic because it has one carbon atom and three oxygen atoms. Also has negative charge, so it is an ion (anion). That's why it is a polyatomic ion.Mg⁺ has a positive charge (cation) so it is an ion but it has only one magnesium atom so it is not polyatomic.Ne⁺⁻ it's not quite right, the common form it is Ne⁺. This is an ion because it has positive charge (cation), but it is not polyatomic beacuse there is just one neon atom.