nuclear physics - $α$-decay and electron

I'm a Web developer and I'm working on a physic interactive Web page to represent how atoms interact. I'm reading information about α-decay and here is what I understand.

Let's say we have a isotope ²²²Rn that will change, after more than 3 days, into a ²¹⁸Po because it will release a "small ⁴He nuclei" at 5 % the speed of light.. I've got 2 questions.

First, what is going on in those 3 days, what is happening. Does the nuclei is "unstable", vibrating ?

Second, where does the electron go?