An ionic bond is the electrostatic forces of attraction between a non-metal and a metal ion in a giant ionic crystal lattice. This occurs when charged atoms (ions) attract. This happens after a metal atom loses one or more of its electrons to the non-metal atom. The greater the difference in charge between the metal and non-metal ion, the stronger the ionic bond. A maximum of three electrons can be transferred in the process.
A metal atom becomes a positive cation because it loses electron(s). A non-metal atom becomes a negative anion as it gains electron(s). This occurs, for example, when sodium and chlorine join to form common table salt, NaCl. First, sodium atoms (Na) oxidize and lose an electron to form positively charged sodium ions (Na+). Chlorine atoms gain the electrons from the sodium atoms to form negatively charged chloride ions (Cl-). Both ions are now oppositely charged and they are held by strong electrostatic forces of attraction.
Features of ionic bonds[change | change source]
- Three dimensional ionic structure called a giant ionic crystal lattice structure.
- Ionic compounds are soluble in water as the ions form favorable interactions with water molecules which release sufficient energy to break away from the lattice.
- In a solid state they do not conduct electricity. However, in a liquid state or when dissolved in water, they will conduct electricity well because the ions are free to move and can carry charge.
- They contrast to the characteristics of a covalent bonds.
- Sometimes if they do not have a spare valence electron to create a complete shell one will act as two and spin in a figure of eight around both atoms.
- Ionic bonds are generally a lot weaker than covalent bonds.
- Ionic compounds have high melting/boiling point due to the strong electrostatic forces of attraction, which require a large amount of heat energy to overcome.