1. The problem statement, all variables and given/known data What is the value of the principal quantum number for a hydrogen atom to have a size of one micron? 2. Relevant equations r=(5.3x10-11)(n2) r=1x10-6/2=5x10-7 3. The attempt at a solution 5x10-7=(5.3x10-11)(n2) 97.1 = n How is this possible? lol Maybe it's more complicated then I'm thinking.