Displacement laws (Soddy and Fajans)
Radioactivity · Physics
Bohr atom
Interactive 3DElectrons orbit the nucleus in shells — switch element to see H, He and Li fill their shells.
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Study notes
Complete the decays: (a) ²³⁹₉₄Pu → ___ + ⁴₂He; (b) ³²₁₅P → ___ + e⁻ + ν̄; (c) A nucleus undergoes 2 alpha and 2 beta-minus decays starting from ²³²₉₀Th. What is the final nucleus? Solution: (a) Alpha: Z −2, A −4 → ²³⁵₉₂U (uranium-235). (b) Beta-minus: Z +1, A same → ³²₁₆S (sulphur-32). (c) After 2α: A = 232 − 8 = 224, Z = 90 − 4 = 86. After 2β⁻: A = 224, Z = 86 + 2 = 88 → ²²⁴₈₈Ra (radium-224).