quartz, sio₂, is the most common mineral found on the surface of the earth. what can you conclude about the…

quartz, sio₂, is the most common mineral found on the surface of the earth. what can you conclude about the fact that quartz is hard and has a high melting point as opposed to other oxides like no₂ and co₂?\na quartz crystals consist of positive and negative ions that are attracted to one another.\nb quartz crystals are extended structures in which each atom forms strong covalent bonds with all of its neighboring atoms.\nc quartz crystals are formed under extremes of temperature and pressure.\nd silicon and oxygen atoms are especially hard because of their electronic structure.

quartz, sio₂, is the most common mineral found on the surface of the earth. what can you conclude about the fact that quartz is hard and has a high melting point as opposed to other oxides like no₂ and co₂?\na quartz crystals consist of positive and negative ions that are attracted to one another.\nb quartz crystals are extended structures in which each atom forms strong covalent bonds with all of its neighboring atoms.\nc quartz crystals are formed under extremes of temperature and pressure.\nd silicon and oxygen atoms are especially hard because of their electronic structure.

Answer

Brief Explanations:

Quartz ($SiO_2$) is a covalent - network solid. In covalent - network solids, atoms are held together by a continuous network of strong covalent bonds. This gives the material high hardness and a high melting point. Options A refers to ionic bonding which is not the case for quartz. Option C about formation conditions does not directly explain the hardness and high melting point. Option D is incorrect as the hardness is due to the bonding network, not just the electronic structure of individual atoms.

Answer:

B. Quartz crystals are extended structures in which each atom forms strong covalent bonds with all of its neighboring atoms.