In the network of silica (SiO₂), each silicon atom is surrounded by __________ oxygen atoms.

Silica (SiO₂), also called silicon dioxide, is a major constituent of the Earth’s crust and is found in minerals like quartz, sand, and flint. Its chemical and physical properties are closely linked to its network structure. In the silica lattice, each silicon atom is covalently bonded to four oxygen atoms in a tetrahedral arrangement.

Each oxygen atom, in turn, is shared between two silicon atoms, creating a continuous three-dimensional network of Si–O–Si linkages. This extensive tetrahedral network is responsible for many of silica’s characteristic properties:

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  High melting and boiling points: The strong covalent bonds in the Si–O–Si network require a large amount of energy to break.

  
  


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  Hardness: Silica is extremely hard due to the rigidity of the tetrahedral network.

  
  


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  Chemical stability: The Si–O bonds are very strong, making silica resistant to most acids and bases.

  
  

The tetrahedral coordination also explains the formation of different polymorphs of silica, such as quartz, cristobalite, and tridymite, all of which maintain the basic SiO₄ tetrahedral units connected in different arrangements.

In contrast, each silicon atom is not surrounded by 2, 1, or 6 oxygen atoms. Four is the correct number, consistent with the valency of silicon (4) and the tetrahedral geometry.

Understanding this coordination is essential in inorganic chemistry, materials science, and geology, as it explains the behavior of silica in glass production, ceramics, and natural mineral formation.

Hence, in the network of silica (SiO₂), each silicon atom is surrounded by 4 oxygen atoms (Option A).