Periodic Table

noun A series of radioactive elements that starts with actinium and ends with lead-206, including actinium, thorium, protactinium, uranium, and various isotopes of these elements.

• The actinium series is a radioactive decay chain that starts with the element actinium-227.
• Did you know about the actinium series and how it decays over time?
• Yo, the actinium series is like a chain reaction of radioactive elements.
• The actinium series can be compared to a domino effect, with each element decaying into the next.

noun a type of mineral that has a radiating or star-like crystal structure

• Actinoid minerals are commonly found in metamorphic rocks.
• I heard actinoid minerals are pretty cool to study in geology class.
• Have you seen those actinoid rocks? They're lit!
• His personality was like an actinoid mineral, hard to break through but beautiful once you do.