Question

magnesium acts with sodium say chemical reaction

Answer 1

 it cannot be expected that two metals, both having basic property will react together. Does a +ve charge react with another +ve charge? No! Instead the +ve charge will get attracted to a -ve charge to gain electrical neutrality. The same principle works here too. So, both Na and Mg will react with some non-metals having acidic property, say, Cl (in the form of chloride), F (in the form of fluoride), Br (in the form of bromide) etc and never between themselves. We really cannot have reaction between Na and Mg

Answer 2

Sodium can't react with magnesium as both are metals ( electropositive elements)