The bonds that hold the atoms in metals together are often described as being built upon metal ions that are floating in a sea of electrons. This is because the electrons in the outer shells, or valence shells, of metals are loosely held. The valence electrons are free to move from one atom to another.
The forces of attraction between the negatively charged electrons and the positively charged atoms that have given up valence electrons are what hold the metal together in what is often referred to as a network or array of atoms. The network extends throughout the metal and gives it its strength.
The ability of the valence electrons in metals to move freely and be shared between atoms is what gives metals some of their particular characteristics, such as malleability and the ability to conduct both heat and electric current.