actinium
- 1. All are radioactive and have similar properties to actinium.
- 这些元素都有放射性，而且性质与锕相似。
youdao
- 2. There are three naturally occurring radioactive series - the thorium series, the actinium series, and the uranium series.
- 有三个天然存在的放射系列，即钍系、锕系和铀系。
youdao
- 3. There are three naturally occurring radioactive series - the thorium series, the actinium series, and the uranium series.
- 有三个天然存在的放射系列，即钍系、锕系和铀系。
youdao
