Bohr energy levels (hydrogenic) (E_n = -13.6 Z²/n² eV)

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E_n = -13.6 Z²/n² eV

What each symbol means

SymbolWhat it stands for
ZAtomic number (nuclear charge in elementary charges)
nPrincipal quantum number (n = 1, 2, 3, …)
E_nEnergy of level n (eV), negative = bound

When to use this

Non-relativistic hydrogenic atom (single electron) in Bohr model; ignores fine structure.