1. 김 석 범 MSM Lab. ( Graduate Student ) 2014. 9. 23 디자인과 재료 문제풀 이

2. 2 Problem 2.1 Cite the difference between atomic mass and atomic weight Atomic mass ? Atomic weight ? Atomic weight = Average of each atomic mass

3. 3 Problem 2.4 (1)Cite two important quantum-mechanical concepts associated with the Bohr model of the atom. - electrons are particles moving in discrete orbitals - electron energy is quantized into shells

4. 4 Problem 2.4  Cite two important additional refinements that resulted from the wave- mechanical atomic - electron position is described in terms of a probability distribution - electron energy is quantized into both shells and subshells - each electron is characterized by four quantum numbers (s,p,d,f)

5. 5 Problem 2.4 sub  Why we use “Orbital” method? - Position - Momentum Uncertainty Principle Heisenberg

6. 6 Problem 2.13 Calculate the force of attraction between a K + and an O 2- ion the centers of which are separated by a distance of 1.5nm = 2.05*10 -10 N

7. 7 Problem 2.13 Preview

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10. 10 Problem 2.19 Compute the percent ionic character of the inter-atomic bonds for CsCl For TiO 2 ? AX 2 Crystal Structures

11. 11 Problem 3 sub Why BCC, FCC, HCP are important?

12. 12 Problem 3 sub Why BCC, FCC, HCP are important?

13. 13 Problem 3.3 Show for the BCC crystal structure that the unit cell edge length a and the atomic radius R are related through

14. 14 Problem 3.9 Calculate the radius of an iridium atom, given that Ir has an FCC crystal structure, a density of 22.4 g/cm 3, and an atomic weight of 50.9g/mol

15. 15 Problem 3.28 Compute the atomic packing factor for cesium chloride using the ionic radii in Table 3.4 and assuming that the ions touch along the cube diagonals.  Since 0.732 < 0.939 < 1.0, cubic sites preferred So each Cs + has 8 neighbor Cl -

16. 16 Problem 3.28 Compute the atomic packing factor for cesium chloride using the ionic radii in Table 3.4 and assuming that the ions touch along the cube diagonals.

17. 17 Problem 3.34 A hypothetical AX type of ceramic material is known to have a density of 2.65g/cm 3 and a unit cell of cubic symmetry with a cell edge length of 0.43nm. The atomic weights of the A and X elements are 86.6 and 40.3g/mol, respectively. On the basis of this information, which of the following crystal structures is(are) possible for this material: rock salt, cesium chloride, or zinc blende? CsCl and ZnS