Atomic radius- a measure of the size of its atoms, usually the mean or typical distance from the center of the nucleus to the boundary of the surrounding cloud of electrons.
Electron Affinity-the electron affinityof an atom or molecule is defined as the amount of energy released or spent when an electron is added to a neutral atom or molecule in the gaseous state to form a negative ion.
Electronegativity-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, and values range down to caesium and francium which are the least electronegative at 0.7.
Lonization energy- qualitatively defined as the amount of energy required to remove the most loosely bound electron, the valence electron, of an isolated gaseous atom to form a cation.
4.8A
12/2.5=4.8, the current in this wire should be 4.8A
Nier Bohr
These are the valence electrons-
And of course, all the action,
All the chemistry occurs the valence shell,
Because chemical bonds between valence electrons.
