Why does copper form Cu²⁺ in reaction with silver nitrate?

[mdsa12]

Homework Statement

Complete the simple displacement reactions and balance any chemical reactions.

Homework Equations

copper + silver nitrate → __________ + ____________

The Attempt at a Solution

Since copper on the periodic table can be Cu²⁺ or Cu⁺, my solution was
copper + silver nitrate → copper (I) nitrate + silver

The answer says: copper (II) nitrate. I don't know why this works when NO₃^- has a 1- charge.

 

[Borek]

Cu²⁺ is the most common and most stable copper ion, especially in aqueous solutions. Charge on NO₃^- doesn't matter, as it is only a spectator.