Nuclear Radiation and Radioactive Decay | 核辐射与放射性衰变

📚 Nuclear Radiation and Radioactive Decay | 核辐射与放射性衰变

In Edexcel A Level Physics, Topic 11 (Nuclear Radiation) explores the nucleus, the nature of radioactive emissions, and the mathematics of exponential decay. Understanding these ideas is essential for solving problems on half-life, activity, decay equations, and for evaluating the uses and risks of ionising radiation.

在 Edexcel A Level 物理中，第 11 章（核辐射）探讨原子核、放射性发射的本质以及指数衰变的数学。理解这些概念对求解半衰期、活度、衰变方程以及评估电离辐射的用途和风险至关重要。

1. The Nuclear Model of the Atom | 原子的核式模型

Rutherford’s alpha-scattering experiment fired alpha particles at a very thin gold foil. Most particles passed straight through, but a small number were deflected through large angles and about 1 in 8000 bounced back towards the source.

卢瑟福的 α 散射实验将 α 粒子射向极薄的金箔。大多数粒子径直穿过，但少数粒子发生大角度偏转，大约每 8000 个中有 1 个被反弹回来。

These results showed that the atom is mostly empty space, with a tiny, dense, positively charged nucleus at its centre and electrons orbiting around it. The nuclear model replaced the earlier plum pudding model.

这些结果表明原子大部分是空的，中心有一个极小、致密、带正电的原子核，电子绕核运动。核式模型取代了早期的葡萄干布丁模型。

2. Isotopes and Nuclear Notation | 同位素与核素符号

Isotopes are atoms of the same element with the same number of protons (proton number Z) but different numbers of neutrons. They therefore have the same chemical properties but different physical properties such as mass and stability.

同位素是质子数（质子序数 Z

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