Types of bonding & property

Bonding in solids

Every atoms are held together in said by interatomic force. These forces actong between the atom are electrostatic in nature. The process of holding atom together in a crystal is known as bonding.
Types of bonding in solids on the basis of electron distribution or forces.

1.ionic bond:- These bond are formed in crystal in which electron are transferred from one atom to another atom. Such that the crystal is made up of positive ion or negative ion. It is non-directional in nature. Its bonding energy is of order of 5ev to 10ev.
Example:- Nacl, CaO etc.
Properties of ionic bonds
1. They have higher enthalpies of fusion and vaporization than molecular compounds.
2.They are hard.
3.They are brittle.
4.They have high melting points and also high boiling points.
5.They conduct electricity but only when they are dissolved in water.

2. Covalent bond:- These bond in crystal are formed by sharing of electron equally between neighbouring atom. It is directional in nature. Its crystal are brittle and hard. It is less strong than ionic bond. Example:-chlorine, diamond etc.
Properties of covalent bond
1.-Low boiling points and melting points.
2. Various colors.
3. Poor conductors of heat and electricity.
4.Brittle solids.

3. Metallic bond:- In crystal with these bond. The valence electrons of constituent atom free to move through out the crystal. They do not form the permanent bond Example:- copper,silvar etc.
Properties of metallic bond.
1.Malleability.
2.Ductility.
3.High melting and boiling point.
4.High electrical and thermal conductivity.
5.Metallic lustre.

4. Vandar waal bond:- In this bond crystal arises due to dipolar force between atom of the crystal. its a weak binding. With low melting and boiling point.
Example:- Argon, neon etc.
Properties of Vandar waal bond.
1. These bonds are weak force of attraction.
2. Low melting and boiling point.
3. Low electrical and thermal conductivity.
4.  This bond break easily.
5. Metallic lustre

5.Hydrogen bond:- The hydrogen bond is formed between an atom of hydrogen and extremely electronegtive atom.Example:- fluorine, oxygen, nitrogen etc. It is essentially ionic in chracter. Example:- Hydrogen water and ice.
Properties of hydrogen bond.
Solubility: Lower alcohols are soluble in water because of the hydrogen bonding which can take place between water and alcohol molecule.
Volatility: As the compounds involving hydrogen bonding between different molecules have a higher boiling point, so they are less volatile.
Viscosity and surface tension: The substances which contain hydrogen bonding exists as an associated molecule. So their flow becomes comparatively difficult. They have higher viscosity and high surface tension.
The lower density of ice than water: In the case of solid ice, the hydrogen bonding gives rise to a cage-like structure of water molecules. As a matter of fact, each water molecule is linked tetrahedral to four water molecules. The molecules are not as closely packed as they are in a liquid state. When ice melts, this case like structure collapses and the molecules come closer to each other. Thus for the same mass of water, the volume decreases and density increases. Therefore, ice has a lower density than water at 273 K. That is why ice floats.

HYDROGEN BONDING