Chemical Bonding

Question 1

Metallic

Answer 1

• Electrostatic attraction between metal cations and sea of delocalised valence electrons
• Sea of delocalised electrons easily maintains a flow of charge through the lattice
• Non-directional bonding allows cations to form interactions with valence e allowing to be malleable
• conductive as they have both mobilised and charged particles
• (lustrous) Light rays are reflected off the delocalised sea of electrons
• Strong metallic bonds holds layers of tightly packed cations in fixed positions
• high melting and boiling points

Question 2

Ionic

Answer 2

• Electrostatic attraction between alternating metal cations & non-metal anions
• Consists of rigid 3D crystalline lattice of alternating metal cations & non-metal anions
• Cannot conduct electricity in solid form as all charged particles within the substance are held in a fixed position and are unable to transfer charge through the compound
• Can conduct electricity in molten state as the bonds are broken and the ions are now mobile and capable of carrying electrical current throughout the substance
• Strong ionic bonds which means they have high melting & boiling points
• Not malleable or ductile as when force is applied, like charges align making it repel and shatter

Question 3

Covalent Molecular

Answer 3

• bonds between 2 or more non-metal atoms
• covalent substance atoms will tend to share their valence electrons rather than gain or lose them completely
• intramolecular forces hold the atoms within the molecules, this force is very strong and requires a lot of energy to break
• intermolecular forces in between molecules and are very weak
• low melting and boiling points
• Consist of neutral molecules and as such, do not have free electrons. Since there are no freely mobile charged particles, they don’t conduct electricity
• The weak intermolecular forces mean that the atoms are easily pushed past each other

Question 4

Covalent Network

Answer 4

• bonding of two or more non-metal atoms
• Giant 3D lattice
• Between each atom are extremely strong covalent bonds that require high levels of energy to break
• have very high melting and boiling points as there is no intermolecular forces and only intramolecular forces which are very strong
• No free electrons or mobile charged particles to carry the charge through the network lattice (except graphite)
• The strong covalent bonds between each atom, together with the large number of these bonds in the lattice, make covalent network substances extremely hard (except graphite)
• If the lattice shears it will disturb the three-dimensional matrix and shatter
• most cases covalent networks won’t be conductors of electricity as each atom is held in a fixed position by covalent bonds and valence electrons are shared between atoms