The RAND function returns numbers from the interval [0,1), and if you need to generate numbers from another interval, you should use the following formula: =RAND() * (bâa) + a. This will return random numbers from the interval [a,b) - greater than or equal to a, and less than b.
At the time, 5.4 was made available as a beta release alongside the stable 5.3.4 release. Now that 5.4 has become the latest stable Unity release, it seems the company intends to keep the program going a beta version of Unity 5.5 is slated to debut in the near future. source.
Most of these answers seem to be effectively saying, 8 electrons form a stable shell because the valence shell has 8 slots and a full shell is the most stable configuration, but I think the real question being asked is, why does the valence shell have 8 slots in the first place?.