Which statement best describes the changes in bonding and energy that occur when a molecule of iodine (I_2) is converted from a solid to a gas?

• A. Covalent bonds within I_2 molecules are formed, and energy is released.
• B. Intermolecular forces are overcome, but covalent bonds within I_2 molecules remain intact; energy is absorbed.
• C. Covalent bonds within I_2 molecules are broken, and energy is released.
• D. Intermolecular forces are strengthened, and energy is absorbed.

Answer: (B)

Verified step by step guidance

1. Step 1: Understand the difference between covalent bonds and intermolecular forces. Covalent bonds are strong bonds holding atoms together within a molecule, while intermolecular forces are weaker attractions between separate molecules.
2. Step 2: Recognize that when iodine (I_2) changes from solid to gas, the molecules themselves do not break apart; instead, the forces holding the molecules together in the solid state are overcome.
3. Step 3: Identify that the covalent bonds within each I_2 molecule remain intact during the phase change because the molecule itself does not dissociate into atoms.
4. Step 4: Know that overcoming intermolecular forces requires energy input, so energy is absorbed during the transition from solid to gas.
5. Step 5: Conclude that the correct description is that intermolecular forces are overcome, covalent bonds remain intact, and energy is absorbed.