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Metals can exist in a range of forms including allotropes and alloys - Leaving Cert Engineering - Question a - 2020
Question a
Metals can exist in a range of forms including allotropes and alloys. (i) Explain the term allotrope. (ii) Identify structure A and structure B, shown. (iii) With... show full transcript
Worked Solution & Example Answer:Metals can exist in a range of forms including allotropes and alloys - Leaving Cert Engineering - Question a - 2020
Step 1
Explain the term allotrope.
Answer
An allotrope is a different physical form in which an element can exist. Allotropes arise from the different ways in which atoms can be arranged or bonded together within a substance. For example, carbon can exist as both diamond and graphite, where the arrangement of carbon atoms defines their respective properties.
Step 2
Step 3
With reference to the allotropy of iron, outline the difference between the properties of structure A and the properties of structure B.
Answer
The body-centred cubic (BCC) structure of iron, known as alpha iron, has atoms at each of the eight corners of a cube with an additional atom at the center. This structure tends to be hard and brittle. In contrast, the face-centred cubic (FCC) structure of iron, referred to as gamma iron, has atoms at each corner of the cube and one atom in the center of each face. This arrangement allows FCC metals to be softer and more ductile compared to BCC, making them more malleable under stress.