Transcript best ppt
Periodic Trend Nuclear charge Reactivity atomic size or radius bonding characteristics ionization energy crystal configurations electron affinity acidic properties electronegativity densities metallic character Atomic radius Periodic Properties Atomic Radii 02: 02 Ions and Ionic Radii Chapter 06 5 Ions and Ionic Radii Trend of ionic radii The cation of an atom decreases in size while the anion of an atom increases in size. The trend can not be made according to the periodic table, but by the isoelectronic series. The more positive an ion is the smaller it is because Zeff(effective nuclear charge) increases, while the more negative an ion, the larger it is because Zeff decreases. Ionization Energy Defined as the amount of energy necessary to remove the outermost electron from an isolated neutral atom in the gaseous state to infinity. Abbreviation is Ei, it has units of kJ/mol. IE Successive ionization energy Ionization Energy Minor irregularities in the Ei values are explained by looking at the electron configurations. IE Trend Ionization Energy Ionization energies vary periodically, which is explained by the changes in Zeff . Zeff Electron Affinity Electron Energy: Energy change that occurs when an electron is added to an isolated atom in the gaseous state. Abbreviation is Eea, it has units of kJ/mol. Values are generally negative because energy is released. Value of Eea results from interplay of nucleus electron attraction, and electron–electron repulsion. EA Electron Affinity 02 EA Trend Chemical recativity http://www.youtube.com/watch?feature=player_d etailpage&v=uixxJtJPVXk (group 1 reactivity) http://www.youtube.com/watch?v=u2ogMUDBaf4 &feature=player_detailpage (halogen reactivity) Metallic Character The metallic character of atoms can be related to the desire to loose electrons On the periodic table, the metallic character of the atoms increase down a family and decreases from left to right across a period.