Atomic Radius The atomic radius of a chemical element is a measure of the: Distance from the nucleus to the boundary of the surrounding cloud of electrons.

Atomic Radii

Ionization Energy Ion- atom or group of bonded atoms that has a positive or negative charge. Ionization-any process that gives an ion. Ionization energy-energy required to remove one electron from a neutral atom of an element

Electron Affinity Electron Affinity- the energy change that occurs when an electron is acquired by a neutral atom Sometimes atoms gain electrons easily and sometimes they are forced to gain them by adding energy Groups 2, 12, 18- ZERO AFFINITY Full valence electron shell

Ionic Radius The radius of an atom’s ion Ion=Different Number of Electrons Trend: Down to Francium (Fr) and to the right (Halogens) Outer Edges are bigger than the middle

Valence Electrons Valence Electron: the electron(s) that are able to be gained, lost, or shared with another atom to make a bond Valence: outside; perimeter; edge Main Group Elements…We will not do transition metals at this time. 

VE=Valence Electron Group 1: 1 VE Group 2: 2 VE Group 13 (3): 3 VE For Groups 13-18 (main group) just take off the one of the group number to get the VE number. Group 18 has full Valence shell He is being the bad brother with a full shell with 2 e-

Electronegativity Def: is a measure of the tendency of an atom to attract a bonding pair of electrons. The Pauling scale is the most commonly used. Fluorine (the most electronegative element) is assigned a value of 4.0. Caesium and Francium which are the least electronegative are assigned a value at 0.7. Trend: Increases up the chart and to the right