The shells of clams and oysters collect on the seafloor. over time they form a rock. what type of rock is it

Since the shell of oysters and clams are formed from calcium carbonate id guess it would turn into limestone 

hope that helps

Non metal is an element or substance that is not a metal metal is a solid material that is typically hard, shiny, malleable, fusible, and ductile, with good electrical and thermal conductivitymetalloid is an element (e.g., germanium or silicon) whose properties are intermediate between those of metals and solid nonmetals. they are electrical semiconductors.