Solid Iodine (I₂)
* Appearance: Solid iodine is a dark gray to black, shiny, crystalline solid.
* Particles: Iodine exists as diatomic molecules (I₂), meaning two iodine atoms are covalently bonded together. These molecules are arranged in a regular, repeating pattern, forming a crystal lattice.
* Arrangement: The molecules are held together by relatively strong intermolecular forces called van der Waals forces. This is why iodine has a relatively high melting point (113.7 °C).
Gaseous Iodine (I₂)
* Appearance: Gaseous iodine is a purple vapor.
* Particles: Iodine molecules (I₂) are still the basic unit, but they are now widely spaced and move freely.
* Arrangement: The molecules are far apart and move randomly, colliding with each other and the walls of their container. This random motion is what gives iodine its characteristic purple color in the gaseous state.
Key Points:
* Diatomic Nature: Iodine exists as I₂ molecules in both solid and gaseous states.
* Intermolecular Forces: The strength of intermolecular forces dictates the state of matter. Stronger forces (solids) lead to a more ordered arrangement, while weaker forces (gases) allow for greater freedom of movement.
* Color: The color of iodine is due to the absorption and emission of light by the I₂ molecules. The color changes with the state of matter due to the different energy levels of the molecules.
Let me know if you have any other questions about iodine!
