The human ABO blood type is a good example of multiple alleles. Humans can have red blood cells that are of type A (I A), type B (I B), or type O (i).he human ABO blood type is a good example of multiple alleles. Humans can have red blood cells that are of type A (I A), type B (I B), or type O (i).
Not all of them do. Water is a highly polar solvent. Water molecules can interact strongly with ions, forming a shell around them that also screens the ions from each other. An ionic compound will dissolve readily if the interaction energy between the ions and water is energetically (what physicists call the free energy) favorable compared to the solid salt. 1.5k Views Â· View Upvoters
1 Most crystals are ionic compounds. 2  This is because the ions in these compounds tend to stack into crystal lattices to balance between the attractive forces between opposite ions and the repulsive forces between like ions. 3  Covalent or molecular compounds can exist as crystals, though. Ionic compounds tend to have higher melting and boiling points than covalent compounds. 2  Ionic compounds tend to be hard and brittle while covalent compounds tend to be softer and more flexible. 3  Ionic compounds conduct electricity when dissolved in water while covalent compounds typically don't.