👉 The periodic weapon, also known as the actinide series or actinide contraction, refers to a group of elements in the periodic table that span from atomic numbers 89 (actinium) to 103 (lawrencium). These elements exhibit unique and often extreme properties due to their partially filled 5f orbitals, which lead to actinide contraction—a phenomenon where the effective nuclear charge experienced by the outer electrons increases more significantly across the series than in other groups. This contraction results in smaller atomic and ionic radii, enhanced nuclear stability, and distinct chemical behaviors, making the actinides more chemically similar to each other than to the preceding transition metals. Elements in this series include uranium, neptunium, plutonium, americium, curium, berkelium, californium, einsteinium, fermium, madisonium, roentgenium, and lawrencium.
