Hydrogen Radial Density P(r) = r²|Rnℓ(r)|²

Increase ℓ by 1: lose a radial node, keep the same energy — the accidental Coulomb degeneracy in one plot.
n = 2, ℓ = 0
E = −3.40 eV
Radial nodes = 1
⟨r⟩ = 6.00 a₀
Peaks in P(r) = 2