METALLIC BOND AND ROLE OF ELECTRONS IN METALLIC PROPERTIES

Since metallic bonds involve loosely-bound electrons, there can be a relatively large number of probable orientations for a metal bond. In other words, the bonds are weak and non-directional. This characterizes metals as tending to crystallize in relatively close-packed structures with a large number of nearest neighbours.

Metallic Bond

Metals are all good conductors of heat and electricity. Hence you find them in electric cables, light bulbs, circuits and cooking pans. For example, Cu, Al, and Ag are very good conductors of electricity; comparatively, lead (Pb) is not such a good conductor of electricity. Most common metals like tin, copper, and chromium do not dissolve or react with water. This is the reason why we use such metals in making pots, and pans for cooking and why drinks and foods are sold in tin cans.

Metallic atoms are held by electrostatic forces, joined in a particular way that makes them what they are. The metallic properties of a given metal, depend on the behaviour of the atoms of the metallic elements. The outer electrons of most metal atoms tend to be weakly held to the atomic nucleus.

Consequently, these outer electrons are easily dislodged, leaving behind positively charged metal ions. The electrons dislodged from a large group of metal atoms flow freely through the resulting metal ion grid. This "fluid" of electrons holds the positively charged metal ions together in a type of chemical bond known as a metallic bond.

Role of electrons in Metallic Properties

Activity

Metal ions are held together by freely flowing electrons. These loose electrons form a kind of "electronic fluid" that flows through the lattice of positively charged ions. The mobility of electrons in metal accounts for the metal's significant ability to conduct electricity and heat. Also, metals are opaque and shiny because the free electrons easily vibrate to the oscillations of any light falling on them, reflecting most of it.

Furthermore, the metal ions are not rigidly held to fixed positions on the grid, as ions are in an ionic crystal. Rather, because the metal ions are held together by a "fluid" of electrons, these ions can move into various orientations relative to one another, which is what happens when a metal is pounded, pulled, or moulded into a different shape.

Since metal atoms pack together very closely in a giant structure, metals tend to be heavy. When a metal is hammered, the closely packed atoms slide around each other making the metal malleable. Similarly, the electrons in the outer shells of the atoms can move around the giant structure, so metals conduct electricity.