Question

Question #67208

Answer 1

Phosphorus is located in group 15 of the periodic table and has an atomic number equal to 15. This means that a neutral phosphorus atom has a total of 15 electrons.

The ground state electron configuration for phosphorus is

`"P": 1s^(2) 2s^(2) 2p^(6) 3s^(2) 3p^(3)`

I'll use the noble gas shorthand notation from this point on.

`"P": ["Ne"] 3s^(2) 3p^(3)`

Now, an excited state configuration has one electron promoted from a lower to a higher energy level. Looking at the ground state configuration, you could have one electron from the `"3s"` sub-level promoted to the `"3p"` sublevel. The electron configuration will be

`"P": ["Ne"] 3s^(1) 3p^(4)`

Another possibility is to have one electron from the `"3p"` sub-level promoted to the `"4s"` sub-level

`"P": ["Ne"] 3s^(2) 3p^(2) 4s^(1)`

Yet another possibility is to have one electron from the `"3p"` sub-level promoted to the `"3d"` sub-level, skipping the `"4s"` sub-level altogether

`"P": ["Ne"] 3s^(2) 3p^(2) 3d^(1)`

Read more on how to determine excited state configurations here:

http://socratic.org/questions/how-do-you-determine-excited-state-electron-configuration