Question

Classify each substance in the table as either a metallic, ionic, molecular, or covalent network solid

Short answer

X is ionic, Y is metallic and Z is covalent network solids.

Step-by-step solution

To classify each substances 

	Metallic solid	Covalent solid	Molecular solid	Ionic solid
Electrical conductivity	Good conductors of heat and electricity	Poor conductors of heat and electricity	Poor conductors of heat and electricity	Poor conductors of heat and electricity
Melting point	Melting point depends strongly on electronic configuration	high	Low	Relatively high melting point
Appearance	Malleable, ductile, lustrous	Hard,brittle and dull	Soft and dull surface	Hard,brittle and dull
Solubility in water	Insoluble	Insoluble	Insoluble	soluble

Hence Based on the table shown in the detailed section we can say that X is ionic, Y is metallic and Z is covalent network solids.