What happens when a cloud forms?

I'm looking specifically for an explanation of condensation nuclei. Do the water molecules bond with it and each other? Or do they just form around it and bond to each other with their hydrogen bonds. And do they freeze as soon as they gather? If so, are they stuck hydrogen bonded to each other and/or the condensation nucleus? And, how big is the condensation nucleus compared tot he water molecules? Any other details or things I should know? So you know, I'm trying to write a story from the perspective of a water molecule, starting from when the cloud forms to when it rains, so please try to explain everything on a molecular or atomic level. Please and thank you, so so much!What happens when a cloud forms?
Adam gave you a good answer but, to add a little bit in the style I use when I teach meteorology to aviators, here is what I know:

Water needs to give away thermal energy when going from gas to liquid (condense) and liquid to solid (freeze). Likewise, it must take thermal energy when going from solid to liquid (melt) and liquid to gas (evaporate). The latter is the reason the evaporation of our sweat cools down our skin.



The problem is that when water condenses as it cools down by the adiabatic effect of a lesser pressure aloft, it needs something with a mass to transfer that thermal energy. That is why e.g. cloud seeding with silver oxide is done to precipitate condensation and, ultimately, rain.



This is also why we see dew on about anything with a mass, when the temperature falls under the dew point, usually early in the morning.



The same applies to water under freezing point. When in tiny droplets, it becomes under-cooled water that only freezes when meeting e.g. the leading edge of the wing of my aircraft; hence the danger of "freezing fog."



But the most interesting point is that the tiny droplets that form a cloud has to cool down to form larger droplets, otherwise they simply evaporate with time. It is only when the air is still warmer than the surrounding and rises, that rain can form. Hence, all rain starts first upward. And in some case, it rises all the way to the top of the troposphere, what we call, the tropopause, and freezes into pellets of ice. When it eventually comes down, it is as hail.What happens when a cloud forms?
Raindrops mostly form around dust particles - if not, then they form around salt molecules or other impurities in the air. A raindrop never really forms purely by the action of water molecules alone (technically/probabilistically it's possible - but effectively never actually occurs). Those small particles are then propelled by small wind vortices (a localized micro-turbulence) within clouds that force the small particles out to the outer edge of the vortices/clouds, where they begin to smash together and condense in order to achieve a mass sufficient to overcome the wind currents within the clouds and begin falling. Because the drops originate at different points and with different velocities, small drops form larger drops as they fall and combine with others.What happens when a cloud forms?
Why do clouds form and why does it rain?

Air, even "clear air," contains water molecules. Clouds exist in the atmosphere because of rising air. As air rises and cools the water in it can "condense out", forming clouds. Since clouds drift over the landscape, they are one of the ways that water moves geographically around the globe in the water cycle. A common myth is that clouds form because cooler air can hold less water than warmer air鈥攂ut this is not true.



As Alistair Fraser explains in his Web page "Bad Meteorology", "What appears to be cloud-free air (virtually) always contains sub microscopic drops, but as evaporation exceeds condensation, the drops do not survive long after an initial chance clumping of molecules. As air is cooled, the evaporation rate decreases more rapidly than does the condensation rate with the result that there comes a temperature (the dew point temperature) where the evaporation is less than the condensation and a droplet can grow into a cloud drop. When the temperature drops below the dew-point temperature, there is a net condensation and a cloud forms,