`CO_(2)` exists in the gaseous state, whereas `SiO_(2)` is a hard solid though both carbon and silicon belong to the same group. Give reasons.

Explanation

To understand why CO₂ exists as a gas while SiO₂ is a hard solid, we need to analyze the nature of their structures and bonding.

### Step 1: Identify the molecular structure of CO₂
CO₂ (carbon dioxide) is a molecular compound. It consists of individual CO₂ molecules that are held together by weak intermolecular forces (specifically van der Waals forces).

### Step 2: Identify the molecular structure of SiO₂
SiO₂ (silicon dioxide), on the other hand, has a giant covalent structure. In this structure, each silicon atom is covalently bonded to four oxygen atoms in a three-dimensional lattice. This creates a strong network of bonds throughout the solid.

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