7 Written questions
6 Multiple choice questions
- Metallic mixtures
- 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.
- formed between atoms of different radius, where the smaller atoms fill the interstitial spaces between the larger atoms
- Good: electrons are delocalized and relatively free to move
- density is usually between that of the component metals; alloy remains malleable and ductile
- 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
6 True/False questions
Substitutional Alloy (definition) → formed between atoms of comparable radius, where one atom substitutes for the other in the lattice
Optical properties of metal (explained) → When light falls on a metal it is almost totally absorbed since the bonding electrons can jump up to a broad band of energy levels allowing energy changes corresponding to the full range of frequencies in the visible region of the spectrum.
These currents immediately re-emit the light out of the metal thus providing a strong reflection if the metal surface is smooth.
Water solubility of an ionic solid → Soluble: the charged ions interact with the dipoles on the water molecules.
Identification of an ionic solid → Non-conductive (insulators): ions are pinned by the rigid lattice.
Conductivity of alloys → Good: alloys usually retain a sea of mobile electrons (delocalized covalent bonds) and so remain conducting (for both HEAT and ELECTRICITY)
Conductivity of an ionic solid → Non-conductive (insulators): ions are pinned by the rigid lattice.