A=metallic bond is formed in metals. Let's take the example of copper. The copper atoms are arranged in a certain manner in a copper metal. Here the valence electrons are free to move around in a piece of copper metal. These valence electrons are attracted towards the positive cores of copper. This results in metallic bonding. 

b=A chemical metallic bond is formed when two metallic atoms share the valence electrons. A point noteworthy is, the valence electronics of any region of the metal atoms can be shared to form metallic bonds.


Any metallic element has metallic bonds: 
Copper, zinc, sodium, lithium, francium, iron, cobalt, calcium, magnesium, silver, gold, barium, platinum, chromium are a few. 
Electrostatic attraction between the positively charged atomic nuclei of metal atoms and the delocalised electrons in the metal. Properties of metals.

platinum, copper, iron, anything metallic element that has metallic bond.