CHEM一問! 急!!!

gaint covalent structure
．All atoms are held together by strong covalant bonds
．melting and boiling point : high
．Do not conduct electricity
．Hardness and strength : hard
．Solubility : insoluble in water and non-aqueous solvent
e.g Diamond (carbon atoms), Quartz(oxygen atoms and silicon atoms)..

simple molecular structure
．Molecules are held together by weak van der waals' forces
Atoms are held together by strong covalant bonds
．melting and boiling point : Low
．Do not conduct electricity
．Hardness and strength : soft and brittle
．Solubility : slighty soluble or insoluble water and soluble in non-aqueous solvent
e.g iodine crystals (iodine melecules) , dry ice (carbon dioxide melecules)

simple molecular structure...there s still a force inside...its call ""van der Waal's force""... this is a weak force and the force is use to hold the structure of molecule together...the boilding point is low...easy to break...
gaint covalent structure it very strong bonding...diamond is one of the example...very high melting& boiling pt.
i hope i can help you

中五程度呢只係要知書入面果幾種giant covalent...
姐係silicon dioxide(quartz)...carbon(diamond)...
其他covalent compounds都係simple molecular