Chemistry (11th Grade)
Unabbreviated Electron Configuration
What is the correct unabbreviated electron configuration for iron?
1s2 2s2 2p6 3s2 3p6 4s2 3d6
1s2 2s2 2p6 3s2 3p6 4s2 3d7
1s2 2s2 2p6 3s2 3p6 4s2 3d6 4p1
1s2 2s2 2p6 3s2 3p6 4s2 3d6 4p6 5s2