They are all things you can do to elements on the periodic table?
The solubility is the guide to the maximum amount of solute that can be dissolved in a certain amount of solvent at a certain temperature to make a saturated solution. Any amount less than this would result to unsaturated, while any amount more would result to saturated.
6 g/(50 mL * 1 L/1000 mL) = 120 g/L
Since it is less than the solubility of 125 g/L, then <em>this solution is unsaturated</em>.
If the element has a charge of +2 it has lost two electrons giving it an overall positive charge making it a cation. In order to find the number of electrons, take the elements atomic number and subtract two since it lost two electrons
Step 
<u>find the mass of a single washer</u>
Divide the total mass by the number of washers


Step 
<u>Convert kg to mg</u>
we know that

so

therefore
<u>the answer is</u>

Answer:
I'm thinking cooper but not sure