J.R. S. answered • 07/18/17
Tutor
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Ph.D. in Biochemistry--University Professor--Chemistry Tutor
The Bohr model suggests that the higher the energy of an electron, the further away from the nucleus it is. Thus, he numbered the energy levels (n) with 1 being closest to the nucleus, 2 being next, 3 after that, etc. Today, based on the current periodic table, the highest value for n would be 7 since there are 7 periods (n=7). So, the answer to your question would be the 7th shell. The reason is that as an electron moves away from the nucleus, it becomes less stable (no attraction to the + nucleus), and the less stable an electron is, the more energy is possesses.
