Explanation: this is a double replacement reaction meaning that the two reactants that are compounds switch. Al has an oxidation charge of +3 and OH has an oxidation charge of -1 it becomes subscript 3 to make it even 3 x -1 is -3. Since this is a chemical reaction you may have to balance it by using coefficients on either side of the equation. For this problem you need to use a coefficient of 3 in front of NaCl and NaOH with x being AlOHsubscript 3 since there’s only 1 OH on the reactants side.
Sodium has 11 protons and Magnesium has 12. The way that the periodic table is set up doesn't allow for any elements to be in between. The element would have to have 11.5 protons, which is impossible
