In a word equasion, eg Copper (II) Flouride, what does the "(II)" mean?

Charge is expressed in Roman numerals.

(II) this is two in roman.

Copper (II) Fluoride meaning:

The charge on copper is two.

Why isn't the charge on fluorine expressed? Because we know all halogens are -1 in charge.

We know the charge of almost all on except the transitions.

The transition elements have multiple charges. Copper has multiple charges not just 2 but it can also have a charge of 1. Copper 2 & 1 also have different properties and colors and solubility. This difference in charge brings a difference to properties of that element.

Rule of thumb: Write the charges

Cu2+ F1-

Take the absolute value and criss cross and drop!

CuF2 that's that simple.

So your equation is CuF2