Covalent Bonding

Question 1

Explain the use of -ide and -ate on the end of ionic compounds

Answer 1

-ide = metal and non metal
-ate = metal, non metal and oxygen

Question 2

What’s a covalent bond?

Answer 2

A shared pair of electrons - results in the formation of molecules

Question 3

What types of substances do covalent bonds form?

Answer 3

Simple Molecular, Giant Covalent

Question 4

What are the properties of Simple molecular substances?

Answer 4

Contain Covalent bonds

• Low Melting/Boiling points as although atoms within molecules are held together by covalent bonds, the molecules are held together by weak intermolecular forces
• Don’t conduct Electricity (no free ions/electrons to carry the charge)
• Some are soluble, some aren’t
• Mostly gases/liquids at room temp
• Melting and boiling points increase as molecules get bigger as the strength of the intermolecular forces increases with size

Question 5

What are the explained properties of the 3 carbon-based giant covalent structures?

Answer 5

DIAMOND - Each carbon atom bonded to 4 other carbon atoms with covalent bonds. High MP/BP. Rigid lattice structure makes it really strong (cutting tools). Doesn’t conduct electricity (no free electrons/ions)
GRAPHITE - Each carbon atom bonded to 3 other carbon atoms with covalent bonds. Each carbon atom has 1 delocalised electron to carry the charge (conducts electricity, used to make electrodes). Sheets of carbon atoms in hexagons with the layers held together by weak forces of attraction so they can slide over each other (good lubricating material, soft, slippery)
GRAPHENE- 1 layer of Graphite, 1 atom thick = 2D

Question 6

Explain Fullerenes with examples

Answer 6

• Molecules of carbon shaped like closed tubes or hollowed balls
• used to cage other molecules when the fullerene forms around another atom/molecule, trapping it inside
• used to deliver drugs directly to cells in the body
• Huge surface area makes them good industrial catalysts where individual catalyst molecules could be attaches to the fullerenes
  E.G. Buckminsterfullerene(C60) - Hollow sphere of 20 hexagons and 12 pentagons. Stable molecule that forms soft brownish-black crystals
  E.G. Nanotubes - Cylinders of Graphene, conduct electricity, strengthens sport equipment due to high tensile strength and low weight