3.3 Metallic bonding

Question 1

What is metallic bonding?

Answer 1

A lattice of positively charged ions in a sea of delocalised e-

Question 2

What does the number of delocalised e- depend on?

Answer 2

How many e- have been lost by each metal atom

Question 3

How do metals have giant structures?

Answer 3

Metallic bonding spreads throughout

Question 4

What is the name for the e- that are free to move about in a metal?

Answer 4

Delocalised e-

Question 5

Why are metals good conductors of electricity?

Answer 5

• Have delocalised e- that can move throughout the structure and carry charge

Question 6

Why are metals good conductors of heat?

Answer 6

• energy is spread by increasingly vigorous vibrations of the packed ions

Question 7

What does the strength of the metal depend on?

Answer 7

• charge of the ion
• size of the ion

Question 8

How does the charge of the ion affect the strength of metals?

Answer 8

• The greater the charge = the greater the no. of e-
• the stronger the electrostatic force of attraction between the +ve ions and the e-

Question 9

How does the size of the ion affect the strength of the metals?

Answer 9

• the smaller the ion = the closer the e- to the +ve nucleus
• the stronger the bond

Question 10

Describe the structure of solid magnesium and how its ions are held together

Answer 10

• the valence e- shell in each Mg atoms is delocalised
• makes +ve Mg2+
• attracted to delocalised e-
• the attraction holds the lattice together

Question 11

Which out of a 2+ ion and a 3+ ion have a higher melting point?

Answer 11

3+ ion
- has a higher nuclear charge = more delocalised e-
- stronger electrostatic force of attraction
- more energy needed to be overcome

Question 12

Why are metals malleable and ductile?

Answer 12

Malleable (beaten into shape)
Ductile (pulled into thin wires)

• after distortion, each metal ion is still in the same environment
• retains its new shape

Question 13

Why do metals have a high melting point?

Answer 13

• have giant structures
• strong (electrostatic force of ) attraction between metal ions and delocalised e-
• need lots of energy to be overcome