Final answer:
Iodine (I2) is a solid at room temperature and hydrogen (H2) is a gas because iodine has stronger dispersion forces due to its larger size and higher electron count, leading to higher melting and boiling points for iodine compared to hydrogen.
Step-by-step explanation:
The reason I2 is a solid at room temperature while H2 is a gas has to do with the intermolecular forces between the molecules. Iodine has stronger dispersion forces because it is a larger molecule with more electrons, making those forces significantly stronger compared to hydrogen. These forces are strong enough to keep iodine molecules together in a solid form at room temperature. On the other hand, hydrogen, which is a much smaller molecule with fewer electrons, exhibits weaker dispersion forces, allowing it to be in the gaseous state at room temperature.
The correct answer to the question is: A) Iodine has a stronger intermolecular force. This is because larger and heavier atoms and molecules like iodine exhibit stronger dispersion forces than smaller and lighter atoms, such as hydrogen. As a result, iodine has higher melting and boiling points compared to hydrogen, making it a solid at room temperature while hydrogen remains a gas.