chem - liquids and solids

Question 1

What are the properties of each of the following, and what are they grouped as?

Ionic solids –
Metallic solids –
Covalent network solids –
Molecular solids –

Answer 1

The 4 types of intermolecular forces within solids:

Ionic solids – are held together by ionic bonds, making them hard, brittle, non-conductive in solid form, and have high melting and boiling points.

Metallic solids – are held together by a “sea” of freely flowing electrons around a lattice of metal cations, making them malleable, ductile, and conductive.

Covalent network solids – are held together by a network of covalent bonds, making them hard, non-conductive, and have high melting points.

Molecular solids – are held together by intermolecular forces, making them soft, non-conductive, and have low melting points.

Question 2

Amorphous vs crystalline solids

Answer 2

Amorphous: no unit cell
(ex: glass, gel, plastic, rubber, and tar)

Crystalline: defined by a unit cell (the smallest, individual, repeating unit of the crystal lattice)
(ex: salt, sugar, graphite, quartz, and diamond)
- 3 types:
- simple cubic (1 atom/unit, 1/8 of each 8 atoms corner)
- body-centered cubic (2 atoms/unit, 1/8 of each 8 atoms corner and 1 full one in the middle)
- face-centered cubic (4 atoms/unit, 1/8 of each 8 atoms corner, 1/2 on each 6 faces)