In a silica tetrahedron, the small brown sphere at the center typically represents which type of atom?

• A. Oxygen (O)
• B. Carbon (C)
• C. Silicon (Si)
• D. Hydrogen (H)

Answer: (C)

Verified step by step guidance

1. Understand the structure of a silica tetrahedron: it consists of a central atom surrounded by four oxygen atoms arranged in a tetrahedral geometry.
2. Recall that silica (SiO\_2) is composed of silicon and oxygen atoms, where silicon is the central atom bonded to four oxygen atoms.
3. Identify that in typical ball-and-stick or space-filling models, the central atom in a silica tetrahedron is silicon (Si), often represented by a distinct color such as brown or yellow.
4. Recognize that oxygen atoms are usually shown as smaller spheres surrounding the central silicon atom, often in red or another color different from silicon.
5. Conclude that the small brown sphere at the center of the silica tetrahedron represents the silicon (Si) atom.