@Agamemnon Well essentially atoms of elements don\'t look anything like the images used to portray them, they are only used to aid understanding. But in order to have seperate elements, there needs to be a different number of electrons, which means to balance it there must be a different number of protons and neutrons in the nucleus, which greatly increases the 'gravity' of the nucleus, causing it to pull on the orbiting electrons more which should cause them to speed up to remain in orbit. I\'m not sure if this is right but I take it that some argue the number is higher because once an element reaches 8 electrons in an orbiting level, it has to form a new level further away from the nucleus, which would decrease the pull on the electrons.