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In class today, Dr. Lavelle discussed how electron distortion and polarizability can predict states of matter for certain molecules (like methane and pentane). I'm having a little trouble understanding how the size or molar mass can predict if a molecule is a solid, liquid, or gas. If someone could explain that again, I would really appreciate it. Thanks!
The larger an atom is, the more electrons it has. The more electrons the atom has, the greater likelihood of depolarization of said electrons. This polarization is what creates dispersion forces between atoms or molecules. Therefore, the larger the atom/molecule is, the greater polarization ability it has and thus attractive forces. This is why Lavelle used Iodine and bromine in his example in the lecture. Due to its size, iodine is solid at room temp while bromine is liquid and smaller in size.
As mentioned above, larger atoms and molecules have more electrons that are in higher energy levels and therefore further away from the nucleus, making them less tightly bound. In the context of molecules, the electrons are able to be more easily distorted and stronger intermolecular forces take place. The strength of the intermolecular forces helps indicate the state of matter of substances as well as their boiling points, for example. Weaker intermolecular forces indicate gases, while ones stronger than that are liquids, and even stronger intermolecular forces indicate the substance would be a solid.
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