Question

How is the order of energy of atomic orbitals established?

Answer 1

1. According to the Aufbau principle in the ground state of an atom, an electron will occupy the orbital of lowest energy, and orbitals are occupied by electrons in the order of increasing energy.
2. Hence the order of energy of atomic orbitals is established based on the Aufbau principle.
3. The order of filling up of the orbitals according to the Aufbau principle is given as:$1\mathrm{s},2\mathrm{s},2\mathrm{p},3\mathrm{s},3\mathrm{p},4\mathrm{s},3\mathrm{d},4\mathrm{p},5\mathrm{s},4\mathrm{d},5\mathrm{p},6\mathrm{s},4\mathrm{f},5\mathrm{d},6\mathrm{p},7\mathrm{s},5\mathrm{f},6\mathrm{d},7\mathrm{p}...$