# Homework Help: Electron Configurations in excited states

1. Oct 16, 2007

### viper2308

1. The problem statement, all variables and given/known data
Which of the following electron configurations correspond to an excited state? Identify the atoms and write the ground-state electron configuration where appropriate.

1s2 2s2 2p4 3s1
[Ar]4s2 3d5 4p1

2. Relevant equations
none

3. The attempt at a solution
I have no idea what to do. I was able to get 1s2 2s2 3p1 is boron but that is only because I thought it said 1s2 2s2 2p1

2. Oct 16, 2007

### eli64

put the last electron back into the previous orbital, - this will give you the ground state. count the total number of electrons, check the periodic table and this will give you the element

3. Jul 4, 2009

### joyousjansuba

well, none of those..

==ground state includes the sub-orbitals of "p", which are: Px,Py,Pz (Well, x,y,and z are supposed to be subscripts and p is in lowercase.)

==it should be:
z=26(right?!)
[Ar] 4s2 3d5 4p1 = 1s2 2s2 2p6 3s2 3p6 4s2 3d5 4p1
==1s2 2s2 2p6 3s2 3p6 4s2 3d5 4px1 4py 4pz

==excited state is more elaborate...

==there...that's it dude..
==well, i suppose you know what's the correct answer,,,
==you've posted a trivia..
==well,,tc:)

4. Jul 5, 2009

### Staff: Mentor

Count the electrons - that will give you total number of electrons and you will know what element you see.

Write - using Aufbau principle - ground state configuration.

Compare - if it is different, you are excited