The element NaCl and Kr crystallizes in a cubic structure. While NaCl is a solid at room temperature, Kr is a gas? The reason for this is:a)NaCl has covalent bonding and Kr has metallic bonding.b)NaCl has ionic bonding and Kr has covalent bonding.c)NaCl has ionic bonding and Kr has Vander Waals interactions.d)NaCl has ionic bonding and Kr has hydrogen bonding.Correct answer is option 'C'. Can you explain this answer?

Question

Answer

Option c
NaCl has ionic bonding while Krypton being a noble gas has vanderwaals radius and hence exists in gasesous state

Answer

Explanation:

1. Ionic Bonding in NaCl:
NaCl (sodium chloride) is an ionic compound where sodium (Na) atom loses an electron to form a cation (Na+) and chlorine (Cl) atom gains an electron to form an anion (Cl-). The opposite charges of Na+ and Cl- attract each other, resulting in the formation of an ionic bond. The strong electrostatic attraction between the cations and anions holds the NaCl crystals together.

2. Vander Waals Interactions in Kr:
Kr (krypton) is a noble gas that exists as individual atoms and does not form bonds in the same way as NaCl. Instead, Kr atoms interact with each other through weak Vander Waals forces. Vander Waals forces are temporary dipole-dipole interactions that arise from fluctuating electron distributions around atoms or molecules. These forces are relatively weak compared to the strong ionic bonds in NaCl.

3. Crystalline Structures:
Both NaCl and Kr crystallize in a cubic structure. In NaCl, the cubic structure is formed by alternating Na+ and Cl- ions, resulting in a repeating pattern of ions. In Kr, the cubic structure is formed by individual Kr atoms arranged in a regular pattern.

4. Solid vs Gas at Room Temperature:
NaCl is a solid at room temperature because the strong ionic bonds between Na+ and Cl- ions hold the crystal lattice together. This requires a significant amount of energy to break the bonds and convert the solid into a liquid or gas.

On the other hand, Kr is a gas at room temperature because the weak Vander Waals interactions between the individual Kr atoms are easily overcome by thermal energy. The relatively low boiling point of Kr allows it to exist as a gas under normal conditions.

Conclusion:
The reason for NaCl being a solid at room temperature and Kr being a gas is the difference in bonding types. NaCl has ionic bonding, where strong electrostatic attractions hold the ions in a crystal lattice. In contrast, Kr has Vander Waals interactions, which are weak forces between individual atoms. These forces are easily overcome by thermal energy, allowing Kr to exist as a gas at room temperature.

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