Which element has the lowest freezing point among all substances?

• A. Oxygen
• B. Helium
• C. Hydrogen
• D. Nitrogen

Answer: (B)

Verified step by step guidance

1. Understand that the freezing point of an element depends on the strength of the intermolecular forces or atomic interactions present in its solid phase.
2. Recognize that all the given elements (Oxygen, Helium, Hydrogen, Nitrogen) are gases at room temperature and have very low freezing points due to weak intermolecular forces (mostly London dispersion forces).
3. Recall that Helium is a noble gas with very weak interactions between atoms because it is monoatomic and has a very small atomic size, leading to extremely low freezing and boiling points.
4. Compare the freezing points of the elements: Helium has the lowest freezing point because it requires the lowest temperature to solidify, followed by Hydrogen, Nitrogen, and Oxygen.
5. Conclude that among the given options, Helium has the lowest freezing point due to its minimal atomic interactions and very weak London dispersion forces.