Na⁺Cl⁻++++++++++++covalenta shared pairionican electron handed overmetallica shared seaH₂, H₂O, plasticstable saltcopper, iron
In a covalent bond two atoms share a pair of electrons, which sits between the nuclei and pulls on both. In an ionic bond one atom takes an electron outright: sodium gives up its single outer electron and chlorine fills its shell with it, and the resulting positive and negative ions attract. In a metal every atom gives its outer electrons to a sea shared by the whole solid, and that sea glues the positive ions together.