Metallic Properties:
Metals are sometimes described as a lattice of positive ions surrounded by a cloud of delocalized electrons. They are one of the three groups of elements as distinguished by their ionization and bonding properties, along with the metalloids and nonmetals. On the periodic table, a diagonal line drawn from boron (B) to polonium (Po) separates the metals from the nonmetals. Most elements on this line are metalloids, sometimes called semi-metals; elements to the lower left are metals; elements to the upper right are nonmetals (see the periodic table showing the metals).
Source: http://wiki.answers.com/Q/Metallic_and_non_metallic_propertyhttp://wiki.answers.com/Q/Metallic_and_non_metallic_property
Atomic radius
The atomic radius of a chemical element is a measure of the size of its atoms, usually the mean or typical distance from the nucleus to the boundary of the surrounding cloud of electrons. Since the boundary is not a well-defined physical entity, there are various non-equivalent definitions of atomic radius
Video:
Atomic radius: http://www.youtube.com/watch?v=fBazliON32I
Metallic properties: http://www.youtube.com/watch?v=ZwTmKApE2Jg
