Atoms and Nuclei: One-Page Formula Sheet

Atoms and Nuclei — formula sheet

Formulas

• Eₙ = −13.6 Z²/n² eV; rₙ = 0.529 n²/Z Å
• 1/λ = RZ²(1/n₁² − 1/n₂²)
• N = N₀e^(−λt), T½ = 0.693/λ
• Nuclear radius R = R₀A^(1/3)

Key ideas

• Bohr orbits: angular momentum = nh/2π
• Spectral series: Lyman (UV), Balmer (visible), Paschen (IR)
• Binding energy per nucleon peaks near iron
• Radioactive decay is exponential

Traps to avoid

• Sign of energy levels
• Mixing decay constant and half-life
• Forgetting Z² for hydrogen-like ions

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