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MSE 235-Materials Science for Electronics Engineers ASSIGNMENT-1 ATOMIC STRUCTURE AND INTERATOMIC BONDING 1)Cite important concepts associated with the Bohr model and wave mechanical model of the atom. 2) (a) Give the electron configurations of Ti; Ti2+, Cu; Cu+, F-, Ca, Ca2+ (b) Calcium Floride (CaF 2 ) exhibits predominantly ionic bonding. The Ca2+ and F- ions have electron structures that are identical to which inert gases? Atomic numbers(Z); Ti=22, Cu=29, F=9, Ca=20) E 4)The net potential energy between two adjacent ions, E N , may be represented by; ro E N = -(A/r) + B/rn (where A and B are constants) a) b) Determine the equilibrium interionic spacing, r o (Hint: derivative of net potential energy with respect to interatomic spacing is zero) Determine the expression for E o Eo r 5) Schematically draw energy (E) versus interatomic separation (r) curves for aluminum and Al 2 O 3 on the same graph and discuss the differences between these curves in terms of bonding energy (E o ), bond length (r o ) and melting points by labelling the critical points on the curve. 6) Briefly cite the main differences between ionic, covalent and metallic bonding 7) The percent ionic character of a bond between elements A and B (A being the most electronegative) may be approximated by the expression; %ionic character = (1-e-(0.25)(XA-XB)2)x100 X A and X B are the electronegativities for the respective elements. Compute the percent ionic character of the interatomic bonds for the following compouns: TiO 8) Determine the number of covalent bonds that are possible for atoms of the following elements: Cl, F. 9) (a) What type of bonding would be expected for each of the following materials and compounds: Poly vinly chloride (PVC) , Brass (Cu-Zn), CaO, NaCl, H 2 0, CO 2 , HCl (b) What type of intermolecular bonding (bonding between molecules) would be expected for each of the compounds; HF-HF, HCl-HCl, H 2 O-H 2 O.