Question

How does 2s orbital differ from 1s?

Answer 1

A `2s` orbital has one more radial node.

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The number of total nodes is

`n-1`,

where `n` is the principal quantum number (`n = 1, 2, 3, . . .`).

The number of angular nodes is given by `l`, the angular momentum quantum number, so the number of radial nodes is

`n - l - 1`.

But for `s` orbitals, `l = 0`, so `n - 1 = n - l - 1` for `s` orbitals. Therefore, since `n` increased by `1`, `2s` orbitals have one more node, and it is of the radial kind.

Knowing that, if the following radial distribution functions consist of either the `1s` or the `2s`, which is which?

HINT: if the radial part of the wave function, `R_(nl)(r)` goes to zero, so does the radial probability density, which is proportional to `R_(nl)^2(r)`.