Which of the following are characteristics of ionic compounds? Check all that apply.
-have high melting and boiling points
-are hard
-can exist as solids, liquids, or gases at room
temperature (25°C)
-are good conductors of electricity when
dissolved in water

A, B, D are correct

have high melting and boiling points are hardare good conductors of electricity when  dissolved in water

Explanation:

Ionic compounds are compounds that are formed between a metal and non-metal with a significant electronegativity difference. The metals transfers their electrons to the non-metals and the electrostatic attraction of the ions brings about the bonding that forms the compound.

Ionic compounds are diverse in nature and form.

Here are some of their properties:

They are usually hard solids with a high melting point or liquids with high boiling pointsThey are soluble in water and non-soluble in non-polar solventsThey are able to conduct electricity in molten form. They undergo very fast reaction in aqueous solutions.

D)can be increased in a closed system

D. most models represent a real world object in a simpler way