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Chemical Bonding (Ionic, Covalent and Metallic): Question 5

Syllabus 2.7

Multiple choice Extended 1 mark

A silversmith is raising a bowl: she starts with a flat, circular disc of silver and repeatedly strikes it with a mallet over a curved wooden former, gradually curving the flat disc into a rounded bowl shape. Even after hundreds of hammer blows, the silver does not split or crack; it just changes shape smoothly. Which statement correctly explains, in terms of structure and bonding, why the silver disc can be reshaped this way without breaking?

Choose an answer to check it, then compare with the worked solution below.
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Worked solution

Step 1: Recall the metallic bonding model

A metal such as silver consists of a giant lattice of positive metal ions surrounded by a “sea” of delocalised electrons. Electrons that are not fixed to one particular atom and are free to move throughout the whole structure. A strong electrostatic attraction between the positive ions and the delocalised electrons holds the lattice together.

Step 2: Apply this to the silversmith’s hammering

Each blow from the mallet applies a force to the flat disc. In response, the layers of positive ions can slide into new positions relative to one another, gradually curving the disc against the wooden former. The delocalised electrons are still free to move and continue to surround the ions wherever they end up, so the electrostatic attraction, and therefore the metallic bond, is maintained throughout. The silver changes shape smoothly rather than splitting or cracking.

Why the other options are wrong

  • B: silver is held together by metallic bonding, not covalent bonding. There are no fixed covalent bonds between individual silver atoms to “stretch”.
  • C: the metallic bonding does not break completely with each blow; if it did, the disc would shatter into separate ions or atoms instead of gradually curving into a bowl.
  • D: this describes a structure that would be rigid and brittle, unable to change shape at all, the opposite of the malleable behaviour that lets the silversmith raise the bowl.

Final answer

The correct statement is A\boxed{\text{A}}: the layers of positive ions slide over one another while the delocalised electrons keep them held together, allowing the silver disc to be hammered into a bowl shape without breaking.