IGCSE Covalent structures

Elements such as  Silicon, diamond and graphite.  Compounds include  SiO₂

• simple covalent molecules
• metallic
• ionic
• giant covalent 

Why is diamond strong?

• It's made of carbon

• It doesn't conduct electricity

• It forms 4 strong covalent bonds in a giant lattice

• So it can cut glass

What element are diamond and graphite made up of?

• A.     Sodium
• B.     Carbon
• C.     Carbon dioxide
• D.     Silicon

Why does graphite conduct electricity?

• Ions are free to move to carry the charge

• Atoms can move

• Free electrons that can move between the layers and carry the charge

Why is graphite so soft and slippery?

• It is made of layers of atoms with weak forces between them

• It is made of small molecules

• It is an ionic compound

• The covalent bonds are weak

What structure is shown in the diagram?

• Diamond
• Graphite
• fullerene

used in cutting tools like drill bits

• diamond
• graphite
• fullerene

What two types of atoms make a covalent bond?

• 2 Nonmetals
• 1 Nonmetal and 1 Metal
• 2 Metals
• 2 Noble Gases

What happens when a simple molecular substance melts or boils?

• The weak intermolecular forces between the molecules break.

• Strong covalent bonds between the atoms of the molecule break.

Why do simple molecular substances have low melting and boiling points?

• The intermolecular forces between simple molecules are weak.

• The covalent bonds holding the atoms together in a simple molecule are strong. A large number of covalent bonds hold the atoms together in simple molecules.