Nature of metallic bonding in solid state What is the reason behind attraction of metal kernels & free electrons in electron sea model?
 A: It's mechanically not that different from dropping a lot of small magnets into a sea of iron filings (or better, magnetite sand). The positively charged metal ions attract the diffuse fermi sea of delocalized electrons, and vice versa. It's the ability of the electrons to delocalize that enables this, and that gives metals unique properties and the ability (usually) to bend and flex in interesting ways.
A: In metallic solids, the constituent particles are orderly arranged positively charged metal ions (called kernels) surrounded by a sea of free electrons. These electrons are mobile and are evenly spread throughout the crystal and flow throughout the crystal like water in sea.
These are produced from those metal atoms that have low ionization energy and can easily lose their valence electrons. 
These electrons are free to move in all directions like molecules of a gas. These mobile electrons are simultaneously attracted by the positive ions (kernels) and hence hold these positive ions together. The force that holds the metal ions together is called the metallic bond. 
Greater the number of mobile electrons, greater the force of attraction, and hence stronger is the metallic bond resulting in high melting and boiling points.
