MCQ Detailed View

Actinides are a series of metallic elements in the f-block of the periodic table. They have atomic numbers from 89 to 103, starting with actinium (Ac, 89) and ending with lawrencium (Lr, 103). These elements are called actinides because they follow actinium in the periodic table.

Actinides are characterized by f-orbital electron filling. Their electronic configuration typically involves electrons entering the 5f orbital, which gives them unique chemical and physical properties. Many actinides are radioactive, with uranium and thorium being the most widely known. This series includes both naturally occurring elements and synthetic elements produced in laboratories.

These elements are densely packed metals with high melting points and multiple oxidation states, which makes them important in nuclear chemistry. Uranium-235 and plutonium-239 are crucial for nuclear fuel and energy production. Their radioactive nature also makes them significant in research, medicine, and military applications.

Other atomic number ranges, such as 97–104 or 101–115, correspond to different element groups, and 36–43 covers a completely unrelated set of transition metals. Recognizing that actinides span from 89 to 103 helps students identify their position in the periodic table, predict chemical behavior, and understand their role in nuclear chemistry.

Inorganic chemistry studies the classification, properties, and reactions of elements, including actinides. Knowing the atomic number range of actinides is essential for understanding their electronic structure, radioactivity, and applications in energy, medicine, and materials science.

The elements with atomic numbers 89 to 103 are therefore classified as actinides, highlighting their position as a distinct group in the periodic table.