covalent bonding

What is a covalent bond

A shared pair of electrons between two non-metals

Give two examples of simple molecules formed by covalent bonding

H2, H2O

Draw the dot and cross diagram for a hydrogen molecule

H × H (or H• •H )

Why do covalent bonds form between non-metal atoms?

To achieve a full outer electron shell by sharing electrons

State 3 properties of simple covalent molecules

Low melting/boiling points, don’t conduct electricity,

Usually insoluble in water

What is a double covalent bond?

Two shared pairs of electrons

Draw the dot and cross diagram for methane

××

H × C × H

××

H H

What is giant covalent bonding

Millions of atoms covalentlh bonded in a 3D lattice

Compare melting points: simple covalent vs giant covalent structures

Simple = low (weak intermolecular forces)

Giant = very high (many strong covalent bonds)

Why does graphite conduct electricity but diamond does not

Graphite has delocalised electrons between layers

Diamond has all there electrons used in bonding