1.5 Solid Structures

Question 1

Describe the crystal structure of sodium chloride

Answer 1

• giant ionic crystal lattice
• made up of Na+ and Cl- , held together with strong electrostatic attraction
• sodium ions are smaller than chlorine ions

Question 2

Describe the crystal structure of caesium chloride

Answer 2

• giant ionic, crystal lattice
• made up of Cs+ and Cl- , held together with strong, electrostatic attraction
  -ions are all similar size so ions of the same type don’t come in contact

Question 3

name 2 giant covalent structures formed from carbon atoms

Answer 3

Graphite
Diamond

Question 4

describe the structure of graphite

Answer 4

• each carbon atom is bonded to 3 other carbon atoms
• layers of hexagonal rings of carbon atoms form
• weak, intermolecular forces between layers
• one delocalised electron per carbon atom

Question 5

what are the properties of graphite?

Answer 5

• soft because there are only weak intermolecular forces between layers
• conduct electricity, because there is one delocalised electron per carbon atom

Question 6

Describe the structure of diamond

Answer 6

-all carbon atoms are covalently bonded to 4 other carbon atoms
-no delocalised electrons

Question 7

what are the properties of diamond?

Answer 7

-very hard
-very high, melting point
-does not conduct electricity, because there are no charged particles

Question 8

what are the uses of graphite?

Answer 8

-electrodes: conduct, electricity, and has a high, melting point
-lubricant: is a slippery, the layer slide over each other

Question 9

Describe the structure of ice

Answer 9

-lower density than water, but takes up a greater volume
-presence of hydrogen bonding between water molecules

Question 10

what type of structure is iodine

Answer 10

Simple molecular compound
-covalent bonds between the iodine, atoms and weak, temporary dipole interactions between the molecules

Question 11

describe metallic bonding

Answer 11

Occurs in metals. The positive metal ions are held together in a sea electrons.

Question 12

Explain the electrical conductivity of ionic compounds

Answer 12

They cannot conduct electricity when solid
Able to conduct when molten or aqueous because ions are free to move

Question 13

explain the electrical conductivity of a covalent compound

Answer 13

Generally do not conduct electricity because there are no free charge particles

Question 14

explain the electrical conductivity of the metal

Answer 14

Able to conduct, electricity, because of delocalised, electrons are free to move