The ram you should be. but I would go to dell's website> Support> Drivers downloads, and get the manual for it, it's going to list all compatibilities such as max ram and such.
I don't know about the 11. but if it's alike my inspiron duo (Which is unlikely seeing it's an atom cpu) it's cpu will be hard mounted into the motherboard meaning not removable/changeable, however that being said. only super old computers and the atoms are hard mounted to the best of my knowledge. something else the manual should be able to explain.
What is it running right now? seeing it's a rather small computer it's cooling system might not be able to support a i5 just the same. they're hot little cpus.
Another tip I will give you, if you get all the green lights and find it's upgradeable. reset Cmos (Removing bios battery wait 30 secs replace battery) whenever you have to change something on it. I'm going to guess it's alike my duo in this respect and it was a major mystery to me for a good month as to why the keyboard and touch would no longer work after upgrading to a SSD (Also a very recomendable upgrade while you've got it opened) turns out the power pack battery always supplies power seeing it's fixed inside the case and that being said it messed with the biso having removed the palm rest (Mouse keyboard included) and tricked it into thinking there was none there.
Sorry to ramble. but if I can save you from that pain I will for sure try.