1. The problem statement, all variables and given/known data Recently in my chemistry class my teacher told us that, the greater the atomic number the smaller the radius of the electron. Because there is more protons pulling on electrons. which would mean the elctrons move inwards. This doesnt seem quite right to me as i thought that the distance of electron shells are constant for all atoms, but i cant find any disproofs or paradoxis with this statment so, am I wrong? 2. Relevant equations none, however an electron shell diagram could be usefull 3. The attempt at a solution i was thinking that if electron shells could move then, theoreticly the atom could collapse by the electrons flying into the nucleus. However this doesnt seem to help me or make sense.