柯林斯词典atomic number 1. N the number of protons in the nucleus of an atom of an element 原子序数 ( abbr: at. no. symbol: Also called proton number) 返回 atomic number剑桥词典the number of protons found in the nucleus of an atom of a particular chemical , used as a way of listing the chemical elements in order in the periodic table 原子数（某种化学物质的原子核中质子的数量，用于化学元素周期表中的排序） 返回 atomic number