Describe two shortcomings of the Pennium a model for isotopes:

1. and 2. question: in which equation? or i don't understand you, 3. a), 4. c), 5. c), 6. b), 7. d), 8. d) if small number is underlined(behind symbol) , b) if big number is underlined(in front of symbol)9. what is underlined there? 10. c)

They did not study the continental drift

So3 that’s what i think

Hey : )a transition from the first energy level to the fourth energy level