Metallic Bonding
4 marks · NormalRead the statements about metallic bonding and answer the questions.
State what holds the particles together in a metallic lattice.
Describe what is meant by the term 'delocalised electrons'.
Explain why positively charged ions do not move apart in a metal.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
(a) Electrostatic forces of attraction between positive ions and delocalised electrons.
(b) Electrons that are free to move throughout the structure and are not attached to any one atom.
(c) The positively charged ions are held together by strong electrostatic attraction to the sea of delocalised electrons. This attraction keeps the ions in place and prevents them from moving apart.
Common mistakes: Confusing ions with electrons; Omitting electrostatic force in explanations
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · States that electrostatic attraction/forces between positive ions and delocalised electrons hold the lattice together.
B2 (b) · 1 mark · Describes delocalised electrons as electrons free to move throughout the whole structure or not attached to any atom.
M1 (c) · 1 mark · Describes positively charged ions are surrounded/attracted by delocalised electrons.
A1 (c) · 1 mark · Explains that the electrostatic attraction prevents the ions from moving apart or holds ions in place.
Worked solution
a) The electrostatic forces of attraction between the positive metal ions and the delocalised electrons hold the particles together.
b) Delocalised electrons are electrons that are not attached to any one atom and are free to move throughout the structure.
c) The positive ions in a metal are surrounded by a sea of delocalised electrons. The strong electrostatic attraction between the positive ions and the delocalised electrons keeps the ions together and prevents them from moving apart.