States of Matter

Solids

Solids are the state of matter at which matter is generally the coldest. Solids are generally made up of ordered molecules that are, for the most part, vibrationally locked. Why are they in place? Remember that solids are the state of matter where matter is coolest(generally). This means that temperatures for solids are usually low, so the average kinetic energy(and thus, speed) of the molecules are slow.

There are two main arrangements of solids: crystalline and amorphous. Crystalline solids are nice and well-ordered with a usual pattern molecularly. Amorphous solids are arranged more randomly but they're still more or less locked in place. Usually metals and ionic compounds form crystalline solids but other compounds form amorphous solids.

Above is a brief description of the different types of crystalline solids. These are also expanded upon in this page.

Liquids

Liquids are above solids in the progression of states of matter. The molecules in a liquid are moving around a little bit but not really fast enough to start zooming around in random directions like gas molecules. The intermolecular forces within liquids define many of their fundamental properties.

One property of liquids is known as surface tension. Surface tension results from the intermolecular forces that water molecules exert on another water molecules. This means that within the liquid, water molecules are pulled in every direction. However, at the surface, molecules are pulled down and not up by other molecules, as seen on the diagram. Surface tension makes it so that objects that aren't massive enough will float entirely above the water. This is because if they sink, then the water molecules have to let go of their attractions and make way for the molecules to sink. The stronger the IMFs, the more cohesive the liquid is and the greater its surface tension will be. Obviously, due to surface tension, the molecules won't easily just break up. This applies to any liquid surface.

Another liquid property that relates to the strength of intermolecular forces in liquids is viscosity. The pure physics behind viscosity can be found here. Viscosity is essentially a liquid's resistance to fluid flow. Substances with high viscosities don't flow well, like syrup and honey. The visual differences in flow caused by viscosity are illustrated in the GIF above.

In general, the more complex a molecule's structure is and the greater its IMFs are, the higher its viscosity. This high viscosity of CH₂(OH)CH₂(OH), more easily known as ethylene glycol, can be attributed to its insanely complex molecular structure and strong hydrogen bonding forces between oxygen and hydrogen atoms

Gases

Gases are higher than liquids in temperature so they're the phase above liquids and solids. Gas molecules travel insanely fast because their temperatures are so high that molecules overcame their intermolecular forces. However, the properties are thoroughly expanded on here so we'll leave that info for other pages for you to look at if you'd like.

Melting and Boiling Points