When only metal atoms have the opportunity to interact, neither ionic nor covalent bonding is possible. The transfer of electrons won’t occur because none of the atoms have a strong desire to accept the electrons that others have a desire to give up. Likewise, the sharing of electrons won't take place because none of the atoms would like to possess more electrons. What does occur when metal atoms are around each other is that the loosely held electrons sort of envelop the positive cores of the atoms they don’t have a strong desire to be around individually. In most metals, one or more of the valence electrons become detached from the atoms and migrate in a “sea" of free electrons among the positive metal ions that result from the loss of these electrons. A better way to describe the situation is that the electrons enter delocalized electron orbitals that are not associated with any particular atom but, instead, belong to the whole metal sample. The metallic bond can be envisioned as an attraction to the electrons in the delocalized orbitals by the positive ion cores of the metal atoms. The attractive force strength varies with the amount of positive nuclear charge and the number of electrons in the electron sea.