Atomic Refresher Part 2

This post is another refresher of atomic structure and radioactivity in preparation for the final. I hope this one, as I do the others, will be most helpful for those studying for the final.

Link 1: http://www.chemguide.co.uk/atoms/properties/gcse.html

Link 2: http://www.chemtutor.com/struct.htm

Video: https://www.youtube.com/watch?v=M5HpZFcT01U

Image: http://www.chem4kids.com/files/art/atom-struct-01.png