What actually holds a piece of metal together in metallic bonding?

1. In a metal the valence electrons are delocalised, so they do not stay near one nucleus. 2. The positive atomic nuclei sit in a sea of these delocalised electrons. 3. Metallic bonding is the electrostatic attraction between those positive nuclei and the delocalised electrons. 4. Because the electrons are free to move, metals conduct electricity well. 5. Because the nuclei are packed closely, metals also conduct heat well. 6. Shared pairs sitting between two nuclei describes a covalent bond, not a metallic one. 7. Opposite ions attracting each other describes an ionic bond instead. _Source: Siyavula Physical Sciences Grade 10 (Everything Science, CC BY 4.0), Chapter 6: Chemical bonding_