| 释义 |
atomic numberBrE /əˌtɒmɪk ˈnʌmbə(r)/ NAmE /əˌtɑːmɪk ˈnʌmbər/ noun (chemistry化学) the number of protons in the nucleus of an atom, which is characteristic of a chemical element. Elements are placed in the periodic table (= centre )of an atom , which is characteristic of a chemical element . Elements are placed in the periodic table according to their atomic numbers 原子序数（指原子在元素周期表中的序号） |