Question

The structures of quartz, mica and asbestos have the common basic unit of

• A. (SiO$_4$)$^{4-}$
• B. (SiO$_3$)$^{2-}$
• C. (SiO$_3$)$^{2+}$
• D. SiO$_2$

Hint:

Remember: All natural silicates originate from the \textbf{SiO$_4$ tetrahedron}.

Answer 1

The Correct Option is A

Step 1: Quartz, mica and asbestos are silicate minerals.
Step 2: All silicate minerals are built from the tetrahedral unit \[ \text{SiO}_4^{4-} \] in which one Si atom is bonded to four oxygen atoms in a tetrahedral geometry.
Step 3: These tetrahedra link by sharing corners to produce different structures: - Quartz – 3D network of shared SiO$_4$ units. - Mica – sheet silicate of the same tetrahedral building blocks. - Asbestos – chain silicate again constructed from SiO$_4$.
Step 4: Therefore the fundamental unit common to all is SiO$_4^{4-}$.