I really need help:/ my friend is helping and nobody understands it

Which diagram shows the correct way to represent an ionic compound of magnesium oxide?

Calculate the molarity of each of the following solutions. part a) 0.12 mol of lino3 in 5.5 l of solution part b) 60.7 g c2h6o in 2.48 l of solution part c) 14.2 mg ki in 100 ml of solution

What is the area in square meters of 448 g ai foil that has a thickness of 23921 nm? the density is 2.70 g/cm