Answer:
Actinides
Step-by-step explanation:
We need to Know what does it mean by elements being radioactive.
- Radioactive elements are elements whose atoms are not stable and therefore disintegrates to emit particles such as alpha, beta or gamma particles for them to attain stability.
- In this case, elements known as Actinides are all radioactive.
- Actinides are a series of radioactive elements in the group 3 of the periodic table. They include, thorium, uranium, plutonium, curium, etc.
- Alkaline earth metals are elements in group II of the periodic table and most of them are not radioactive. Examples include, calcium and magnesium.
- Halogens are group 7 elements in the periodic table. They are known to have an octet configuration. They include, Helium, neon, krypton, etc.