Calculate the number density of valence electrons in a certain metallic element given that the element crystallises in a BCC structure with a lattice constant of 0.415 nm, and that the element is monovalent (i.e. each atom has a single valence electrons). Assuming that the mean free path of the electrons is 1.3 nm, calculate the collision time and the conductivity of the element at 350 K, using the classical Drude model of electrical conduction. O a. Electron density = 2.80 x 1028 m 3; collision time 1.03 x 10-14 s; conductivity = 8.13 x 106 'm1 O b. Electron density = 4.56 x 1028 m-3: collision time = 2.45 x 10-14 s; conductivity = 3.88 x 106 0Im-1 O c. Electron density = 6.53 x 1026 m-3: collision time = 2.45 x 10-14 s; conductivity = 9.26 x 105 'm1 d. Electron density 1.40 x 1028 m-3; collision time 1.03 x 10-14 s; conductivity = 4.07 x 106 Q 'm

Calculate the lattice enthalpy of AgCl (s) using the following thermodynamic data. Note that the data given has been perturbed, so looking up the answer is probably not a good idea. CI - CI (g) Enthalpy of dissociation = 223 kJ/mol Ag (g) 265 kJ/mol Cl (g) Enthalpy of formation Electron attachment enthalpy Enthalpy of ionization Enthalpy of formation = -147 kJ/mol Ag (g) 711 kJ/mol AgCl (s) = = = -369 kJ/mol kJ/mol Do you expect the magnitude (absolute value) of this to be larger or smaller than the lattice enthalpy of AgBr (s)?

Consider we have a silicate glass composition, this composition as shown below in percent by weight 15Na₂O +5K₂O + 2.5MgO +9.5 CaO +6 BaO + 5Al₂O3 +57 SiO₂. First, convert this composition to mole percent. Then classify each oxide added to the glass according to Sun's bond criteria. According to this classification, is this composition make glass or not? Min MO K Mg Ca Al Si Valance 1 1 2 2 2 3 4 Dissociation energy per MOX (in Kcal.) 120 115 222 257 260 402 424 Coordination Number 6 9 6 8 8 4 4 Molecular weight of oxides is shown below Oksitier (Molekil Agri): NajO (61.97), K,0 (94.18), MgO (40.31), CaO (56.08), Bao (153.33), ALO, (1015), 50, (60.08) Single Bond Strength (Kcal/mole) 20 13 37 32 33 101 106

Assuming there is an endless chain of atoms with one atom in each unit cell, what is the shape of the phonon dispersion, that is, the vibrational frequency as a function of wave vector o(k)?