Question

24. The order of energy of 2s orbital in hydrogen atom is greater than sodium. This is because
1) H atom has 1s orbital only
2) Zer of Na is greater than H
3) Na is highly reactive alkali metal
4) In sodium, the last electron is filled in 3s orbital where as in hydrogen is in 1s orbital
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Answer 1

Answer:

Dude your question is wrong. Hydrogen doesn't has 2s orbital. It only has 1s orbital and it lies in K shell only since it only has 1 valence electron.

Answer 2

1) H atom has 1s orbital only

For atoms with one valence electron, Koopman's approximation theorem applies. This means that when the atom size grows larger, the energy levels converge (and become more frequent). (Sodium, by extrapolation, has a 2s orbital energy that is much lower.) By analogy, the H atom has the maximum energy for its 2s orbital.

Atoms with a single electron, such as hydrogen,

Because there are no additional electrons in multielectronic systems, the energy of orbitals is solely determined by their primary quantum number.

As a result, all orbitals belonging to the same orbit, such as orbitals 2s and 2p, have the same energy for Hydrogen-like atoms.