text: what are the properties of convalent,ionic,and matallic bonds?   covalent valence electrons are shared between adjacent atoms.   highly directional bonds produce molecules rather than crystals. almost all polymers exhibit this, as do diamond and silicon carbide (unusual ceramics).  ionic metallic element gives up valence electrons to nonmetallic element. tends to produce the crystalline structures we call ceramics. very strong bonds --> high melting points, elastic moduli. imparts hardness, brittleness and insulativity.  metallic involves “free-roaming” valence electrons. tends to produce the crystalline structures we call metals. imparts conductivity, ductility/malleability, opacity and reflectivity.