The motherboards are NOT normal boards and can not be soldered on. Heat will destroy them. Guess this is the future of motherboards now. They are only one sided boards with everything added in layers over layers using some form of adheasive/electrical process to make things stick and connect.
If it can be made - it can be repaired, but is it worth it is another question.
Just fell off
There are electrically conductive adhesives that can put it back without any heat and/or soldering and you may not even need to get a new capacitor - just put the same back, if it's OK