7 Written questions
6 Multiple choice questions
- Alloy formation sometimes alters the chemistry such as the formation of a chemically inert oxide layer in stainless steel.
- Very Low: due to the strong Coulombic interactions of positive and negative ions arranged in a regular three-dimensional array.
- interstitial atoms do not appreciably expand the lattice and so density is often substantially increased; interstitial atoms make the lattice more rigid reducing ductility and malleability
- Good: electrons are delocalized and relatively free to move
- Good: alloys usually retain a sea of mobile electrons (delocalized covalent bonds) and so remain conducting (for both HEAT and ELECTRICITY)
- density is usually between that of the component metals; alloy remains malleable and ductile
6 True/False questions
Optical properties of metals (list and reason) → Shiny, reflective, lustrous: because electrons move freely throughout the metal. Metals are shiny because of the very strong absorption of light by the delocalised bonding electrons.
Water solubility of an ionic solid → Soluble: the charged ions interact with the dipoles on the water molecules.
Malleability and ductility of an ionic solid → Malleable and ductile: deforming the solid does not change the environment immediately surrounding each metal core
Non-polar solubility of an ionic solid → Insoluble: ionic compounds tend not to dissolve in nonpolar solvents because the attractions between ions are much more favorable than the attractions among the separated ions and nonpolar solvent molecules.
Substitutional Alloy (definition) → formed between atoms of comparable radius, where one atom substitutes for the other in the lattice
Conductivity of an ionic solid → Good: electrons are delocalized and relatively free to move