What is an alloy, and illustrate the atomic structure of an iron alloy?

e) (i) An alloy is a mixture of a metal with at least one other element, typically another metal or carbon.

e) (ii)
Here is a diagram showing a model of the atoms in an alloy of iron. The smaller atoms represent the added element (e.g., carbon in steel), disrupting the regular arrangement of the larger iron atoms.

  O O O O
  O o O O
  O O O O
  O O o O

(Please imagine the circles are drawn in a close-packed arrangement similar to Fig. 8.1, with some smaller circles replacing or fitting between the larger ones. Since I cannot draw, I'll describe it: Draw a lattice of large circles, similar to Fig. 8.1, but replace a few of these large circles with smaller circles, or place smaller circles in the gaps between the large circles.)

Here's a textual representation of the diagram you should draw in the box:
Draw a regular arrangement of large circles (representing iron atoms), similar to Fig. 8.1. Then, replace a few of these large circles with smaller circles, or insert smaller circles into the spaces between the large circles. This shows the presence of different-sized atoms disrupting the uniform structure.