[عاطف خليفة]

Types of chemical bonds

* IONIC BOND
- It is usually formed between metals and non- metals.
- Metals

The atom is large in volume- but small in ionization energies and electronegativity so it loses electrons from outer level converting into positive ion (cation).




Non - metals

The atom is small in volume - but high ionization energy and electronegativity. So it gains electrons converting into negative ion (anion).




* Ionic bond

An electrostatic attraction between positive ion (cation) and negative ion to form neutral compound.


N.B.
- As the difference in electronegativity increases between the binding elements (horizontally), the ionic character increases

In ionic compounds the difference in electronegativity >1.7



* General properties of ionic compounds:

I- Structure

Crystal lattice containing the ions in regular pattern

II- Melting and boiling points

They have high melting and boiling points because a great energy is required to break up the attraction between ions

III- Solution in polar solvents

Crystal lattice is broken down (dissolve) in polar solvents

IV- Electrical conductivity

They conduct electricity through free ions in molten or hydrated ions in aqueous solutions.