出典:Wiktionary
出典:『Wiktionary』 (2026/01/18 01:31 UTC 版)
The table is termed “periodic” because it follows the periodic law – when chemical elements are arranged in order of increasing atomic number, elements with similar properties recur at intervals.
periodic table (plural periodic tables)
出典:Wikipedia
出典:『Wikipedia』 (2011/07/14 01:18 UTC 版)
The periodic table (or, more formally, the periodic table of the elements or periodic table of the chemical elements) is a tabular display organizing the 118 known chemical elements by selected properties of their atomic structure. Elements are presented in the periodic table by increasing values of their atomic numbers, the number of protons in their atomic nuclei. While rectangular in general outline, counter-intuitive gaps are included in the horizontal rows ("periods") as needed to keep elements with similar properties together in each vertical column ("group"), such as the alkali metals, the alkali earths, the halogens, and the noble gases.
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a synopsis
a list of marks―(競技なら)―a score-book
the law of periodicity―the periodic law
a school-schedule
the account-books―the books