Chapter 2 - Metals

Question 0

What are group 1 metals called?

Answer 0

Alkali metals

Question 1

List the properties possessed by most metals

Answer 1

• good conductors of electricity in both solid and liquid states. In solid state, conductivity decreases when temp. increases.
• good conductors of heat in liquid and solid state. As consequence, metals feel cold to touch
• malleable and ductile
• at room temp. many are hard, tough and relatively dense.
• most melting points are relatively high

Question 2

What are group 2 metals called?

Answer 2

Alkaline earth metals

Question 3

What are the groups between 2-13 called?

Answer 3

Transition metals

Question 4

Group 1 and 2 metals:

Answer 4

Tend to be softer, a little less dense, have slightly lower melting points than transition metals.

Question 5

What is metallic bonding?

Answer 5

Electrostatic attractions between delocalised electrons and the positive metal ions.

The metal consists of a lattice structure of positively charged ions, surrounded by a sea of mobile electrons. The valence electrons are said to be delocalised. They can move freely through the lattice of metal ions. The positively charged metal ions are attracted to the negatively charged delocalised electrons and these electrostatic attractions hold the metallic lattice together.

Question 6

Explain the conductivity of electricity in metallic substances

Answer 6

In solid state, positive ions don’t act as charge carriers. They remain vibrating about fixed positions within the lattice, as the delocalised electrons move.
In molten state, both positive ions and delocalised electrons are able to move and act as charge carriers.

Question 7

Explain the conductivity of heat in metallic substances

Answer 7

When one end of a metal is heated, the rate of movement (kinetic energy) of the positive ions and delocalised electrons in the heated region increases. The heat energy is conducted along the metal by more energetic electrons and positive ions colliding with less energetic electrons and ions, and because the electrons are delocalised, they can move quickly and freely through the lattice and so heat energy transfer is rapid.

Question 8

Explain melting points in metallic substance

Answer 8

Group 1 metals readily contribute 1 valence electron, group 2 metals readily contribute 2 valence electrons. As a result, group 2 metals will have more delocalised electrons and larger positive charges than group 1 metals. The expectation therefore is that group 2 metals will have stronger metallic bonds, and consequently higher melting points than group 1 metals

Question 9

What is an alloy?

Answer 9

The homogenous mixture formed when one or more other elements are added to a metal.