June 2017 NY Regents Chemistry Exam
31 Which electron configuration represents the electrons of an atom of neon in an excited state? (1) 2-7
Solution: When an electron goes from a lower to a higher energy level, it is in an excited state. The first energy level has a maximum of 2 electrons. Second energy level has a maximum of 8 electrons. Third energy level has a maximum of 8 electrons. If we take a look at choice 3, 2-7-1. It means two electron in the first energy level, seven in the second energy level and one in the third energy level. Since second energy level has a maximum of 8 electrons, we can see that one electron from the second energy level jumped to the third energy level.
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