What is radioactive?In the natural world, where the atomic nucleus unstable, can spontaneously emit radiation, some time into other elements atomic nucleus elements called radioelement.
英
美
- 何谓放射性?在自然界,凡原子核不稳定,能自发地放出射线,过一些时间变成其它元素原子核的元素,叫放射性元素。