The Development of the Periodic Table

These flashcards cover key concepts related to the historical development of the periodic table and major scientific contributions.

Periodic Law

Properties of elements recur periodically when arranged by increasing atomic number.

Law of Triads

A classification system that groups elements with similar properties into sets of three.

Law of Octaves

States that every eighth element shares properties similar to the first when arranged by increasing atomic mass.

Atomic Number

The number of protons in the nucleus of an atom, used as the basis for arranging elements in the modern periodic table.

Mendeleev's Periodic Table

An early version of the periodic table that left gaps for undiscovered elements and was arranged by atomic mass.

Dmitri Mendeleev

A Russian chemist credited with creating the first widely recognized periodic table in 1869.

Henry Moseley

A scientist who revised the periodic table by arranging elements according to atomic number instead of atomic mass.

Glenn T. Seaborg

A chemist who discovered transuranium elements and reorganized the periodic table, placing actinides below lanthanides.

Lanthanides

A series of 15 chemical elements ranging from lanthanum (La) to lutetium (Lu) in the periodic table.

Actinides

A series of 15 chemical elements from actinium (Ac) to lawrencium (Lr), known for being radioactive.