Explain why ionic crystals melt at much higher temperatures than typical covalent molecular crystals

One of the following properties was originally used to arrange elements on the periodic table, but is no longer used to organize the modern version. which property fits this description?

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 most common reason for matter changing its state?