How are atoms arranged in metals?
In a metallic solid atoms are arranged in a lattice-like 3D structure where there is a regular array of metal cations surrounded by a sea of delocalised electrons.
In iron, the atoms are arranged in a lattice like the one shown below. The atoms have lots of shells of electrons surrounding the nucleus.
This means that the outer electrons are held more loosely than the inner electrons, as they do not feel the pull from the positive nucleus as much.
As a result of this, in a metallic solid there are delocalised electrons. These electrons no longer belong to one single atom but will move between atoms in the solid structure.
The properties that we would see as a result of this are that metallic solids are malleable and can conduct electricity.