Like other scientific concepts, the idea of a chemical element has changed considerably over time, since it was first established in the Enlightenment era. In Dmitri Mendeleev's construction of the periodic system, he distinguished between simple substances and elements as defined by their atomic weights. The foundation of the periodic system on the latter concept led to several challenges. For example, the system seemed unable to accommodate the radioactive substances eventually recognised as isotopes. Around 1920, elements were consequently redefined in terms of their atomic numbers, a nuclear property that could be determined by X‐ray spectroscopy. Although this understanding of an element has stood the test of time, new questions turned up relating to the concept of an element following the syntheses of transuranic elements since the early 1940s. These syntheses of very heavy elements have additionally led chemists and physicists to reconsider the criteria for the discovery of a new element. Recently, elements have been officially recognised on the sole ground that a small number of very heavy atomic nuclei were identified. The paper discusses how the notion of an element was modified during different periods of time, the reasons for the modifications, and the values ascribed to them in the communities of chemists and physicists.

中文翻译：

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周期系统和化学元素的概念：从门捷列夫到超重元素

与其他科学概念一样，化学元素的概念自启蒙运动时代首次提出以来，随着时间的推移发生了很大的变化。在德米特里·门捷列夫（Dmitri Mendeleev）的周期系统构造中，他区分了简单物质和原子量定义的元素。周期系统基于后一个概念的基础带来了一些挑战。例如，该系统似乎无法容纳最终被识别为同位素的放射性物质。因此，在1920年左右，元素的原子序数被重新定义，其核性质可以通过X射线光谱法确定。尽管对元素的这种理解经受了时间的考验，自1940年代初以来，随着超铀元素的合成，出现了有关元素概念的新问题。这些非常重的元素的合成还导致化学家和物理学家重新考虑发现新元素的标准。近来，已经以识别出少量非常重的原子核的唯一理由正式承认了元素。本文讨论了如何在不同的时间段修改元素的概念，修改的原因以及在化学家和物理学家社区中赋予它们的价值。唯一的理由是，已经确认了少量的非常重的原子核。本文讨论了如何在不同的时间段修改元素的概念，修改的原因以及在化学家和物理学家社区中赋予它们的价值。唯一的理由是，已确认了少量的非常重的原子核。本文讨论了如何在不同的时间段修改元素的概念，修改的原因以及在化学家和物理学家社区中赋予它们的价值。