Question

what is the next atomic orbital in the series 1s, 2s, 2p, 3s, 3p?
3d
3f
2d
4s

Explanation:

According to the Aufbau principle, the order of filling atomic orbitals is based on the increasing energy of the orbitals. The general order is \(1s < 2s < 2p < 3s < 3p < 4s < 3d<4p\). After \(3p\), the next orbital to be filled is \(4s\). Orbital \(2d\) does not exist as for \(n = 2\), the possible values of \(l\) (azimuthal quantum number) are \(0\) (s - orbital) and \(1\) (p - orbital). For \(n=3\), after filling \(3p\), we first fill \(4s\) (lower energy) rather than \(3d\) (higher energy than \(4s\) in terms of Aufbau order). Orbital \(3f\) also does not exist as for \(n = 3\), the possible values of \(l\) are \(0\) (s), \(1\) (p) and \(2\) (d).

Answer:

4s