AP Chemistry Flashcards: Structure of Metals and Alloys
Written by AP Content Team, Verified for 2026 AP Exams, Last updated: May 2026
Review key ideas with interactive flashcards. This set includes 10 cards to help you master important concepts.
Steel is an alloy of iron and carbon. What type of alloy is it and why?
Steel is an interstitial alloy because the much smaller carbon atoms fit into the spaces between the larger iron atoms in the lattice.
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Steel is an alloy of iron and carbon. What type of alloy is it and why?
Steel is an interstitial alloy because the much smaller carbon atoms fit into the spaces between the larger iron atoms in the lattice.
Define an interstitial alloy.
An interstitial alloy is a mixture formed when smaller atoms fill the empty spaces (interstices) between the larger atoms in a metallic lattice.
Brass is an alloy of copper and zinc, which have similar atomic radii. What type of alloy is brass?
Brass is a substitutional alloy because the zinc atoms are of a comparable size to the copper atoms and can replace them in the metallic lattice.
What allows metals to conduct electricity, according to the 'sea of electrons' model?
The delocalized valence electrons are not bound to any single atom and are free to move throughout the metallic structure, allowing them to carry an electric current.
What is the key structural difference between interstitial and substitutional alloys?
The key difference is the location of the added atoms: in interstitial alloys, smaller atoms occupy the gaps, while in substitutional alloys, similar-sized atoms replace the original atoms in the lattice.
Describe the model used to represent the structure of a metallic solid.
A metallic solid is modeled as a lattice of positive metal ions (cations) immersed in a 'sea' of mobile, delocalized valence electrons that are shared among all the ions.
Define a substitutional alloy.
A substitutional alloy is a mixture formed when atoms of a comparable radius substitute for each other within the crystal lattice of a metal.
To create an interstitial alloy with titanium, would you choose a smaller atom like boron or a similar-sized atom like zirconium? Why?
You would choose a smaller atom like boron, as interstitial alloys require the added atoms to be small enough to fit into the spaces between the larger host metal atoms.
What atomic property is the primary factor in determining whether a substitutional alloy will form between two metals?
The primary factor is having a comparable atomic radius, which allows the atoms of one element to substitute into the lattice of the other without significant distortion.
What is metallic bonding?
Metallic bonding is the electrostatic attraction between an array of positive metal ions and a surrounding 'sea of delocalized' valence electrons.