The article concerns five traditionally difficult issues that chemical educators encounter and how they should be resolved. In some cases I propose the examination of necessary and sufficient conditions in order to cast light on the relationships under discussion. The five educational issues are, the notion that a pH value of seven implies a neutral solution of water and vice versa, the use of Le Châtelier’s Principle, the relative occupation and ionization of 4s and 3d orbitals, the explanation of anomalous electronic configurations and the elements that make up group 3 of the periodic table.

中文翻译：

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必须死的化学教育中的五个想法

这篇文章涉及化学教育者遇到的五个传统上的难题以及如何解决这些问题。在某些情况下，我建议检查必要条件和充分条件，以便阐明所讨论的关系。这五个教育问题是，pH 值为 7 意味着水的中性溶液的概念，反之亦然，Le Châtelier 原理的使用，4s 和 3d 轨道的相对占据和电离，异常电子配置的解释和构成元素周期表第 3 族的元素。