题型：阅读理解 题类： 难易度：普通
湖南省长沙市南雅中学2024-2025学年高三上学期开学考试英语试题
The periodic table of elements is a common sight in classrooms，campus hallways and libraries. The mode periodic table arranges the elements by their atomic numbers and periodic properties（周期性）. Several scientists worked over a century to assemble the elements into this format.
In 1789，French chemist Antoine Lavoisiertried grouping the elements as metals and nonmetals. Forty years later，German physicist Johann Wolfgang Dobereiner observed similarities in physical and chemical properties of certain elements. He arranged them in groups of three in increasing order of atomic weight and called them triads，observing that some properties of the middle element，such as atomic weight and density，approximated the average value of these properties in the other two in each triad.
A breakthrough came with the pu blication of a revised list of elements and their atomic masses at the first international conference of chemistry in Karlsruhe，Germany，in 1860. They concluded hydrogen would be assigned the atomic weight of 1 and that the atomic weight of other elements would be decided by comparison with hydrogen. For example，carbon，being 12 times heavier than hydrogen，would have an atomic weight of 12.
In 1869，Russian chemist Dmitri Mendeleev created the framework that became the moder periodic table，leaving gaps for elements that were yet to be discovered. Mendeleev predicted the properties of some undiscovered elements and gave them names such as"eka-aluminum"for an element with properties similar to aluminum. Later "eka-aluminum"was discovered as gallium.
German chemist Lothar Meyer produced a version of the periodic table similar to Mendeleev's in 1870. He left gaps for undiscovered elements but never predicted their properties. The Royal Society of London awarded the Davy Medal in 1882 to both Mendeleev and Meyer. The later discovery of elements predicted by Mendeleev verified（证实）his predictions and his periodic table won universal recognition. In 1955 the 101st element was named mendelevium in his honor.
On UNESCO website，it wrote，"The Periodic Table of Chemical Elements is more than just a guide or catalogue of the entire known atoms in the universe；it is essentially a window on the universe，helping to expand our understanding of the world around us. "
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