Boiling Point of Sodium is 890 °C

Cambridge IGCSE Chemistry — June 2024

The boiling point of sodium is 890 °C.

What happens to sodium atoms as the temperature of a sample of sodium changes from 950 °C to 900 °C?

1. The atoms move more quickly and bonds are formed.
2. The atoms move more quickly and bonds are neither broken nor formed.
3. The atoms move more slowly and bonds are formed.
4. The atoms move more slowly and bonds are neither broken nor formed.

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Correct Answer: D

• Kinetic Energy: Temperature drops from 950 °C to 900 °C, causing average kinetic energy to decrease so the atoms move more slowly.
• Phase & Bonding: Since 900 °C is still above the boiling point of 890 °C, the sodium remains in the gas phase. Because no phase change occurs, bonds are neither broken nor formed.