Why is i2 a molecular solid

Moreover, the larger the electron cloud is, the easier it can be polarized. So, as a conclusion, the only forces that exist between iodine molecules are relatively weak London dispersion forces. Iodine exists as a solid at room temperature because the strength of these forces are in line with iodine's large electron cloud and polarizability. Elemental iodine is a solid at room temperature.

What is the major attractive force that exists among different I2 molecules in the solid? Chemistry Phases of Matter Changes of State. Stefan V. Now, how good you think they're gonna be as conductors of electricity? Pause the video and think about that. Well, in order to be conductors of electricity, somehow charge needs to move through the solid. And unlike metallic solids, you don't have the sea of electrons that can just move around, so these tend to be bad conductors of electricity.

If you wanna see another example of a molecular solid, this right over here is solid carbon dioxide, often known as dry ice. What you see here is each of these molecules, each carbon, is bonded to two oxygens. It has a double-bond with each of those oxygens. These are covalent bonds that form each of these molecules. But what keeps all of the molecules attracted to each other is, once again, those dispersion forces. And these forces between the molecules are so weak that solid carbon dioxide doesn't even really melt.

It doesn't even go to a liquid state. If you heat it up enough to overcome these intermolecular forces, these dispersion forces, it will sublime, which means it goes directly from a solid to a gas state, and it does that at a very low temperature.

It sublimes at negative And if you've ever handled a dry ice, which I don't recommend you doing without gloves because it will hurt your skin if you do touch it, I actually did that recently at my son's birthday party, we were playing around with dry ice, you don't mess around with this thing because it is so incredibly cold. And at that temperature, it will go from a solid. It won't even melt to a liquid state. It will go straight to a gas state. Now, the last thing I wanna do is think about why different molecular solids will have different melting points.

So let's compare, for example, molecular iodine to molecular chlorine. Each of these can form molecular solid. We looked at iodine a few minutes ago. Which of these would you think would form molecular solids with higher melting points? The two words italicized in the preceding sentence are important. Covalent bonding implies that the forces acting between atoms within the molecule intra molecular are much stronger than those acting between molecules inter molecular , The directional property of covalent bonding gives each molecule a distinctive shape which affects a number of its properties.

Liquids and solids composed of molecules are held together by van der Waals or intermolecular forces, and many of their properties reflect this weak binding. Molecular solids tend to be soft or deformable, have low melting points, and are often sufficiently volatile to sublime directly into the gas phase.

This latter property often gives such solids a distinctive odor. In general, ionic and covalent compounds have different physical properties. Ionic compounds form hard crystalline solids that melt at high temperatures and are resistant to evaporation. These properties stem from the characteristic internal structure of an ionic solid, illustrated schematically in part a in Figure 2. In contrast, as shown in part b in Figure 9.

Covalent substances can be gases, liquids, or solids at room temperature and pressure, depending on the strength of the intermolecular interactions. Covalent molecular solids tend to form soft crystals that melt at low temperatures and evaporate easily. Figure 9. Molecular solids consist of atoms or molecules held to each other by dipole—dipole interactions, London dispersion forces, or hydrogen bonds, or any combination of these. Molecular solids are composed of discrete molecules held together by intermolecular forces.

Because these interactions are relatively weak, molecular solids tend to be soft and have low to moderate melting points. Covalent molecular solids tend to form soft crystals that melt at low temperatures and evaporate easily.

Figure 9.