In the order of filling atomic orbitals, which orbital comes after 3p?

The correct choice is based on the Aufbau principle, which states that electrons occupy orbitals in order of increasing energy levels. In this context, after the 3p orbital is filled, the next orbital to fill is the 4s orbital.

Following the sequence of filling, the order starts with the 1s, then fills the 2s, followed by 2p, then 3s, then 3p. After all the 3p electrons are accommodated, the next orbital is indeed the 4s because it has a lower energy level compared to the 3d orbital. This is a crucial point in understanding how electrons are arranged in atoms.

While 3d is higher in energy than 4s, it is filled after the 4s because of the energy considerations in atoms with more electrons. Therefore, filling progresses to the 4s before moving onto the 3d and then the 4p, confirming that the next orbital after 3p is indeed 4s. This filling sequence is foundational to understanding the electron configuration of elements and the structure of the periodic table.