Finding attractive force between two ions, using Coulombs equation

[SlothNast]

Homework Statement

"Calculate the force of attraction between a K +
and an O 2- ion whose centers are separated
by a distance of 1.5 nm."

Homework Equations

F = [ k (Z1)(Z2) ] / r^2

The Attempt at a Solution

Both valences are filled when K is a + charge and O is a 2- charge. My main problem is I don't know what to use for "Z". I would just use 1 and -2, but the shells are filled and maybe there isn't much attraction at all?

Any help is greatly appreciated, thanks!
Henry

 

[Borek]

You have two IONS - one has charge +1, the other -2. Valences, shells don't matter.

 

[1MileCrash]

You have the charges, you have the distances, and that's what the formula asks for. Just because these are atomic-level particles doesn't mean squat - they are charged particles. Use the formula.