Draw up the formula of the compound formed by magnesium and nitrogen, and calculate what amount

Draw up the formula of the compound formed by magnesium and nitrogen, and calculate what amount of a substance corresponds to 5 g of this substance.

Given:
MgxNy
m (MgxNy) = 5 g
To find:
n (MgxNy) -?
Decision:
1) Since magnesium will exhibit an oxidation state (+2), nitrogen will exhibit an oxidation state (-3); the formula for the unknown substance will be:
Mg3N2;
2) Calculate the molar mass of Mg3N2:
M (Mg3N2) = Mr (Mg3N2) = Ar (Mg) * N (Mg) + Ar (N) * N (N) = 24 * 3 + 14 * 2 = 100 g / mol;
3) Calculate the amount of Mg3N2 substance:
n (Mg3N2) = m (Mg3N2) / M (Mg3N2) = 5/100 = 0.05 mol.
Answer: The amount of Mg3N2 substance is 0.05 mol.