Question

Why do we go down from 4s before 3d

Answer 1

Answer: 4s The electrons are removed from the oribital before the 3d because,

Energy levels

it's a nuclear binder; 3d electrons are more bound to the nucleus than 4S electrons

Step-by-step explanation: The 4s orbital is typically going to be filled before the 3d orbital, the reasoning behind this is because the 4s orbital has a lower energy. The 3d orbital becomes lower in it's energy compared to the 4s orbital when in transition metals. Hence why 3d is before 4s on the configuration scale.

Answer 2

The 4s orbital is filled before the 3d orbital because it has lower energy.

Step-by-step explanation:

The order in which electron orbitals are filled follows a general trend in the periodic table. In the case of the 4s and 3d orbitals, the 4s orbital is filled before the 3d orbital because it has lower energy.

The 4s orbital is closer to the nucleus, which results in a lower energy level compared to the 3d orbital. This means that the 4s orbital can accommodate electrons before the 3d orbital.