在自然界里,有些元素的原子往往有不同的重量,这些不同重量的原子,叫做该元素的同位素。例如,氧有三种同位素,在普通的氧和一切氧化物里面氧的同位素的分配是——99.76％的氧16,0.04％的氧17,和0.2％的氧18。氧的原子核里面有8个带正电的质子,所以这个原子核总共带8个单 In nature, some elements of the atom often have different weights, these different weights of atoms, called the isotope of the element. For example, oxygen has three isotopes. The distribution of oxygen isotopes in normal oxygen and in all oxides is - 99.76% oxygen 16, 0.04% oxygen 17, and 0.2% oxygen 18. There are 8 positively charged protons in the oxygen nucleus, so this nucleus takes a total of 8 single