Which is true of ionic compounds

they are electrically charged either positive or negative

they form hard, brittle crystals with characteristic shapes

they contain no charged particles

they have characteristically low melting and low boiling points

The first one definitely is. An ion is either a positively charged or negatively charged atom. Hope this helps :)

This is what i found on google“ the monomers combine with each other via covalent bonds to form larger molecules known as polymers. in doing so, monomers release water molecules as byproducts. this type of reaction is known as dehydration synthesis, which means “to put together while losing water. in the process, a water molecule is formed.” i hope this you