الموضوع 4: البنية الذرية
AQA · GCSE · Physics الموضوع 4 17:51 سرد باللغة الإنجليزية · ترجمة مدمجة بالإنجليزية + الصينية
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Separate the nucleus from the electrons.
把原子核和电子分开考虑。
Losing an outer electron creates an ion, while radioactive decay changes an unstable nucleus.
失去外层电子形成离子；放射性衰变是发生在不稳定原子核内的变化。
Charge depends on the balance of protons and electrons.
电荷取决于质子数和电子数之差。
Mass number counts protons and neutrons, so removing an electron does not alter the mass number.
质量数计算质子与中子，因此失去电子不会改变质量数。
The drawing is schematic.
这是一幅示意图。
The nucleus is enlarged so it can be seen, not drawn at its real fraction of the atomic radius.
为了看清原子核，图中把它放大，并非按真实的半径比例绘制。
Isotopes have the same proton number but different neutron numbers.
同位素的质子数相同，中子数不同。
A neutral atom has equal proton and electron numbers.
中性原子的质子数与电子数相同。
The same mass number does not identify the same element.
质量数相同不代表同种元素。
Find the proton number first, then compare neutron numbers.
先找质子数，再比较中子数。
The isotope pair is Q and R.
Q 和 R 是同位素。
P and R share a mass number but have different proton numbers, so they are different elements.
P 和 R 虽然质量数相同，但质子数不同，因此属于不同元素。
Distinguish an energy-level transition from ionisation.
区分能级跃迁与电离。
The first can leave the electron bound to the atom; the second removes an electron.
跃迁后电子仍可属于该原子；电离则使电子离开原子。
Most alpha particles pass through; a very small fraction turn back.
大多数 α 粒子穿过，极少数返回。
These observations constrain where the positive charge and mass can be.
这些观察限制了正电荷和质量在原子中的分布。
Connect each observation to its inference.
把每个观察与相应推论连接起来。
Saying only that the model changed does not explain the evidence.
只说模型改变了，并没有解释证据。
Learn what each change explains.
学习每次改变解释了什么。
Detailed experiments behind Bohr and Chadwick are not required for this syllabus.
本课程不要求掌握玻尔与查德威克实验的详细过程。
The reason must connect the model to evidence.
理由必须把模型与证据联系起来。
Age and popularity do not decide whether a physical model explains observations.
模型的年代或受欢迎程度不能决定它是否解释了观察。
The answer is new evidence.
答案是新的证据。
Explain the conflict between the old prediction and the observation, then the feature of the replacement model.
说明旧模型的预测与观察的冲突，再说明新模型如何解释它。
The detector does not necessarily record every decay.
探测器不一定记录每次衰变。
Keep geometry fixed when comparing count rates and subtract background.
比较计数率时保持几何位置不变，并扣除本底。
On a graph of undecayed nuclei against time, the activity at one instant is the size of the tangent's gradient.
在未衰变原子核数随时间变化的图上，某一时刻的放射性活度等于该处切线斜率的大小。
The dashed line approximates the tangent at one hundred seconds.
虚线近似表示一百秒时的切线。
Use the two marked points on that line.
使用这条线上标出的两个点。
The tangent runs from sixty-eight thousand nuclei at nought seconds to twelve thousand at two hundred seconds.
切线从零秒时的六万八千个原子核，到二百秒时的一万二千个。
Use the positive size of the downward gradient: fifty-six thousand divided by two hundred seconds.
取下降斜率的正值大小：五万六千除以二百秒。
The activity is about two hundred and eighty becquerels.
放射性活度约为二百八十贝克勒尔。
Penetration and ionisation are different properties.
穿透能力与电离能力是不同性质。
Alpha has a short range in air but can strongly ionise nearby tissue.
α 在空气中射程短，但能强烈电离附近的组织。
Paper stops alpha and a few millimetres of aluminium stop beta.
纸能阻挡 α，几毫米铝能阻挡 β。
Thick lead reduces gamma intensity; a reduced reading need not mean every gamma ray was stopped.
厚铅降低 γ 的强度；读数下降不表示所有 γ 都被阻挡。
A surviving component does not mean it was the only emission.
仍能测到某一种辐射，不表示它是唯一成分。
Use the sequence of absorber results to identify a mixture.
利用逐步加入吸收材料的结果判断混合辐射。
The result supports a beta–gamma mixture.
结果支持 β 与 γ 的混合辐射。
The old gamma-only answer ignored the component removed by aluminium.
只回答 γ 会忽略被铝阻挡的成分。
In beta-minus decay a neutron becomes a proton.
β⁻ 衰变中，中子变成质子。
Alpha emission removes two protons and two neutrons.
α 发射带走两个质子和两个中子。
Daughter element names are not required here.
这里不要求写出子核元素名称。
The beta particle is created in the nuclear change; it is not an outer electron leaving the atom.
β 粒子产生于原子核变化，不是外层电子离开原子。
Balance the signed atomic numbers as well as the mass numbers.
既要平衡质量数，也要平衡带正负号的原子序数。
Half-life is a time interval.
半衰期是一段时间间隔。
This curve has a half-life of one year: falling from four hundred to two hundred takes the same time as falling from eight hundred to four hundred.
这条曲线的半衰期是一年：从四百降到二百所用的时间，与从八百降到四百相同。
With real count rates, subtract the background before halving.
对于真实的计数率，要先减去本底计数再取一半。
Count intervals rather than entries in the sequence.
计算间隔数，而不是数列中的数字个数。
The statistical pattern predicts a large population, not the decay time of one named nucleus.
统计规律预测大量原子核的行为，不能预测某一个核何时衰变。
Four times one hundred and thirty-eight gives five hundred and fifty-two days.
4 乘 138 得到 552 天。
Distinguish the fraction remaining from the fraction that has decayed.
要区分剩余比例与已衰变比例。
Contamination concerns radioactive atoms being present.
污染指存在放射性原子。
Those atoms also irradiate their surroundings as they decay.
这些原子衰变时也会照射周围物质。
Do not treat the two words as mutually exclusive hazards.
不要把这两个词当成互不相关、互斥的危险。
A contaminated object can irradiate nearby tissue.
被污染的物体能照射附近组织。
A careful comparison states the source and pathway rather than declaring all contamination worse.
认真比较时应说明辐射源与暴露途径，而不是笼统宣称污染总是更危险。
Build a causal explanation from penetration to the tissue receiving energy.
从穿透能力到组织吸收能量，建立因果解释。
Saying that alpha is dangerous is not enough.
只说 α 很危险并不充分。
Each step contributes to the comparison: low penetration helps outside the body but does not protect tissue next to an internal alpha emitter.
每一步都构成比较：穿透能力低有助于保护身体外部，但不能保护紧邻体内 α 辐射源的组织。
Name a precaution and explain its mechanism.
写出具体措施并说明机制。
Generic protective clothing does not explain whether it reduces irradiation or contamination.
笼统说穿防护服，不能解释它减少的是照射还是污染。
Medical exposure is not a natural background source.
医疗照射不是天然本底辐射源。
Dose is measured in sieverts; one thousand millisieverts equal one sievert.
剂量单位是希沃特；1000 毫希沃特等于 1 希沃特。
Halve the source contribution, not the combined source-and-background reading.
应把辐射源贡献减半，而不是把辐射源与本底的总读数减半。
The detector’s recording fraction has not been supplied.
题目没有提供探测器记录的比例。
Forty to twenty is one halving.
40 到 20 是一次减半。
The measured rate sixty-eight is not half of eighty-eight because the background contribution remains.
总读数 68 不是 88 的一半，因为本底贡献仍然存在。
Equal populations are the condition that makes the activity comparison possible.
原子数相同是能够比较活度的条件。
A shorter half-life does not by itself rank doses from arbitrary samples.
仅凭较短的半衰期，不能排列任意样品造成的剂量。
State the comparison and its reason.
先写比较结果，再写原因。
The actual question gives equal numbers of atoms; retain that condition in the explanation.
真实题目给出了相同的原子数，解释时必须保留这个条件。
A tracer must remain detectable during the investigation and then decline promptly.
示踪剂必须在检查期间可检测，然后活度较快下降。
The shortest possible half-life may end the useful signal too soon.
最短半衰期可能使有用信号过早消失。
A source choice needs both the physical property and the purpose.
选择辐射源要把物理性质与用途联系起来。
Diagnostic tracing and deliberate destruction of tissue have different aims.
诊断示踪和有意破坏组织的目标不同。
A large nucleus absorbs a neutron and splits.
大原子核吸收中子后裂开。
Some emitted neutrons are then absorbed by other suitable nuclei. Not every neutron necessarily causes another fission.
部分释放的中子被其他合适的核吸收，并非每个中子都一定引起下一次裂变。
Use nuclei and neutrons precisely.
准确使用原子核与中子。
The products include two smaller nuclei and two or three neutrons, as well as gamma radiation and released energy.
产物包括两个较小的核、两到三个中子，以及 γ 辐射和释放的能量。
A controlled reactor regulates the reaction rate.
受控反应堆调节反应速率。
An uncontrolled chain can release energy rapidly; the number of fissions does not literally grow without limit.
不受控链式反应能迅速释放能量，但裂变数并非真的无限增长。
The question is about nuclei, not atoms forming chemical bonds.
题目讨论的是原子核，而不是原子形成化学键。
Use the nuclear process and the change in mass.
说明核过程与质量变化。
Joining light nuclei, forming a heavier nucleus and converting some mass to energy are the three connected parts of the explanation.
轻核结合、形成较重的核、部分质量转化为能量，是解释中互相连接的三个部分。
Use these questions to decide what to practise.
利用这些问题判断需要练习什么。
Definitions should lead to an explanation, a graph method or a justified source choice.
定义应能支持解释、图像方法或有理由的辐射源选择。
Return to the corresponding worksheet if you can recognise a fact but cannot explain or apply it.
如果只能认出知识，却不能解释或应用，应返回相应练习。
Check nuclear equations by balancing both rows.
通过检查上下两行的总数来核对核方程。