[Surabh K.t]

To put forth my question in a better way i am taking into consideration a beryllium atom.Its electronic configuration is given by 1s2,2s2.Now i have read that the electrons in the same orbital will have same energy.So both the 2s electrons will have the same energy.But the 2s orbital is spherical in shape.Hence both the electrons can be present anywhere in the spherical volume (excluding nodes).what i mean to say is that both the electrons need not be at the same distance from the nucleus and hence their energies should be different.Where am i going wrong?

[Corribus]

Small particles don't obey classical physics. In the quantum landscape, electrons do not have a precisely defined position. The orbital represents a probability distribution- you may see it as a spatial map of where the electron is likely to be on average, but you cannot freeze time and say one electron is here and the other is there. They are both everywhere that the wavefunction allows them to be at the same time. Orbital energies are determined from the spatial probability distribution (wavefunction), not discrete points in space.

[Surabh K.t]

thank you so much