Which statement about copper, diamond, and silicon(IV) dioxide is correcta)Copper and silicon(IV) dioxide have similar electrical conductivityb)In diamond the carbon atoms are covalently bonded as flat sheetsc)In silicon(IV)dioxide the silicon and oxygen atoms are covalently bonded in flat sheetsd)The structure of copper includes a lattice of positive ions

In diamond the carbon atoms are covalently bonded as flat sheets

In silicon(IV) dioxide the silicon and oxygen atoms are covalently bonded in flat sheets

The structure of copper includes a lattice of positive ions

Explanation:

Diamond and silicon(IV) dioxide are covalent network solids. Covalent network solids are made up of atoms joined to one another by covalent bonds to form a giant lattice, The solids are hard and have a very high melting point. They do not conduct electricity. So, for both diamond and SiO2, atoms are covalently bonded to yield flat sheets in a covalent bonded network solid.

Copper is a metallic substance having metallic bonds, a metallic crystal consists of positive ions and a cloud of electrons.

i believe the answer is a.