E- configuration

[Shibhon_Shepard]

Hi, can someone write like exactly what order we are suppose to write the configuration? because i keep getting mixed answers on whether s or d goes first. thanks

[Lauryn Shinno 2H]

When you get to period 3, even though the periodic table makes it look like 4s should go before 3d, it goes afterwards because the 3d orbital has less energy than 4s after 4s is filled. However, when doing the diagram using Aufbau's rule, 4s goes before 3d.

[Gabriela Aguilar 4H]

If the d- orbital is is full and you have to take away electrons then the d -orbital would be written first followed by the s - orbital because it is more favorable to take away electrons from it. It also depends on what the coefficient is .

Ex: Zn: [Ar] 4s^2 3d^10 ---> would be [Ar] 3d^10 4s^2

[I am Sodium Funny]

The d-orbital should always come before the s-orbital as long as it is in a lower energy level (e.g. 3d before 4s)