中国高校自然科学学报编排规范（节选四）６．９．８化学元素与核素的符号１）化学元素符号均为正体，且首字母大写。２）核素的核子数（质量数）必须标注在元素符号的左上角，如‘’Ｎ不宜写成‘’氮或Ｎ１４。３）分子中核素的原子数应标注在核素符号的右下角，如“Ｎ。... Chinese Journal of Natural Science Journals (Extract 4) 6.9.8 Symbols of chemical elements and radionuclides 1) Symbols of chemical elements are both positive and capitalized. 2) The number of nuclei (mass number) of the nuclide must be marked in the upper left corner of the element symbol, such as “N should not be written” nitrogen or N14.3) The number of atoms in the molecule should be marked in the lower right corner of the nuclide symbol , Such as "N ....