CONCEPT MAP: TRENDS IN PERIODIC PROPERTIES.

This document titled "CONCEPT MAP: TRENDS IN PERIODIC PROPERTIES" provides a comprehensive overview of various trends and relationships in periodic properties. It covers topics such as increases and decreases across periods and groups, effective nuclear charge, ionization enthalpy, electron gain enthalpy, electronegativity, oxidizing nature, covalent character of halides, valence with respect to oxygen, strength of oxyacids, atomic size, metallic character, reducing nature, electropositivity, basic character of oxides, hydroxides, and hydrides, thermal stability of carbonates, and screening effect. The document also explores the relationships between different periodic properties and highlights periodic trends in physical and chemical properties. Additionally, it provides a brief history of the development of the periodic table, discussing the contributions of Dmitri Mendeleev, Julius Lothar Meyer, Henry Gwyn Jeffreys Moseley, and Glenn Theodore Seaborg. Mendeleev's organization of elements based on atomic weight and chemical properties, Meyer's organization according to valency, Moseley's proposal to use atomic number, and Seaborg's advocacy for the creation of the Lanthanides and Actinides groups are all discussed. [Extracted from the article]