Types of covalent bonding!

Permanent dipole is when one atom is more electronegative than the other atom.

Why?

Because it has more protons and electrons and therefore a bigger attraction will happen as opposed to another atom who doesnt have many protons and electrrons.

E.g H-Cl

But whenever the dipoles are symetrical to each other e.g CH4The dipoles act in different directions and cancel each other out!

Van der waal forces

Weak intermolecular attraction between very small temporary dipoles in neighbouring moleculele

Ice is less dense than water:

• Ice has an open lattice with hydrogen bonds holding the water molecules apart.
• When ice melts, the rigid hyrdogen bonds collapse so the h20 molecules move closer together.

High melting/boiling point:

• Hydrogen bonds are stronger than any other molecular force
• The hydrogen bonds are also elongated so more force is needed to break them apart