Решение задачи: Периодическая таблица и Периодический закон

Для подготовки к экзамену по теме «Periodic Table and Periodic Law» (Периодическая таблица и Периодический закон), основанной на великом открытии русского ученого Д.И. Менделеева, ниже представлен структурированный материал для коммуникативного высказывания. Билет № 6 Тема: Periodic Table and Periodic Law 1. Introduction The Periodic Law and the Periodic Table of Elements are the foundation of modern chemistry. This great discovery was made by the brilliant Russian scientist Dmitri Mendeleev in 1869. His work allowed scientists to systematize all known chemical elements and even predict the existence of elements that had not yet been discovered. 2. The Periodic Law The original Periodic Law states that the properties of chemical elements, as well as the forms and properties of their compounds, are in periodic dependence on their atomic weights. Later, with the development of physics, it was clarified that these properties depend on the charge of the atomic nucleus, which corresponds to the atomic number \( Z \). 3. Structure of the Periodic Table The Periodic Table consists of horizontal rows called periods and vertical columns called groups. - Periods: There are 7 periods. As we move from left to right across a period, the metallic properties decrease and non-metallic properties increase. - Groups: There are 18 groups (or 8 main groups in the short-period version). Elements in the same group have similar chemical properties because they have the same number of valence electrons. 4. Periodic Trends The table helps to understand how various properties change: - Atomic Radius: Decreases across a period (left to right) and increases down a group. - Electronegativity: Increases across a period and decreases down a group. - Ionization Energy: Generally increases across a period. 5. Conclusion Dmitri Mendeleev’s Periodic Table is a symbol of the power of Russian science. It remains an essential tool for chemists, pharmacists, and technologists worldwide. For students of chemical technology, understanding this law is crucial for synthesizing new biologically active substances and cosmetic products. Основные термины для запоминания: - Atomic number — атомный номер \( Z \). - Atomic mass — атомная масса \( A \). - Chemical properties — химические свойства. - Valence electrons — валентные электроны. - Predict — предсказывать. Этот текст составлен логично и последовательно, что позволит вам уверенно ответить на экзамене, подчеркнув значимость отечественного вклада в мировую науку.