Chemical formula of magnesium
oxide using Criss cross method

Crisscross method is simply writing the charges crossly near each element. Since oxidation number of Mg (metal) is +2 and oxygen (nonmetal) is -2, if we cross them and write next to each; we get Mg2O2 .

explanation: it gains negative electrons, therefore becoming negatively charged. as charge cannot be created, nor destroyed, only transferred, this leaves the wool positive. now that they have opposite charges, the two items attract.