김 석 범김 석 범MSM Lab . ( Graduate Student )

2014. 9. 23

디자인과 재료 디자인과 재료 문제풀이문제풀이

2

Problem 2.1

Cite the difference between atomic mass and atomic Cite the difference between atomic mass and atomic weightweight

Atomic mass ?Atomic mass ?Atomic weight ?Atomic weight ?

Atomic weight = Average of each atomic massAtomic weight = Average of each atomic mass

3

Problem 2.4

(1)(1) Cite two important quantum-mechanical concepts Cite two important quantum-mechanical concepts associated with the Bohr model of the atom.associated with the Bohr model of the atom.

- electrons are particles moving in discrete orbitals - electrons are particles moving in discrete orbitals - electron energy is quantized into shells - electron energy is quantized into shells

4

Problem 2.4

(2)(2) Cite two important additional refinements that Cite two important additional refinements that resulted from the wave-mechanical atomicresulted from the wave-mechanical atomic

- electron position is described in terms of a - electron position is described in terms of a probability distribution probability distribution

- electron energy is quantized into both shells and - electron energy is quantized into both shells and subshellssubshells - each electron is characterized by four quantum - each electron is characterized by four quantum numbers (s,p,d,f) numbers (s,p,d,f)

5

Problem 2.4 sub

(3)(3) Why we use “Orbital” method? Why we use “Orbital” method?

- Position- Position- Momentum- Momentum

Uncertainty PrincipleUncertainty Principle

HeisenbergHeisenberg

6

Problem 2.13

Calculate the force of attraction between a KCalculate the force of attraction between a K++ and an O and an O2- 2-

ion the centers of which are separated by a distance of ion the centers of which are separated by a distance of 1.5nm1.5nm

= 2.05*10= 2.05*10-10-10NN

7

Problem 2.13 Preview

8

Problem 2.13 Preview

9

Problem 2.13 Preview

10

Problem 2.19

Compute the percent ionic character of the inter-atomic Compute the percent ionic character of the inter-atomic bonds for CsClbonds for CsCl

For TiOFor TiO22??

AX2 Crystal Structures

11

Problem 3 sub

Why BCC , FCC , HCP are important?Why BCC , FCC , HCP are important?

12

Problem 3 sub

Why BCC , FCC , HCP are important?Why BCC , FCC , HCP are important?

13

Problem 3.3

Show for the BCC crystal structure that the unit cell edge Show for the BCC crystal structure that the unit cell edge length a and the atomic radius R are related throughlength a and the atomic radius R are related through

14

Problem 3.9

Calculate the radius of an iridium atom, given that Ir has Calculate the radius of an iridium atom, given that Ir has an FCC crystal structure, a density of 22.4 g/cman FCC crystal structure, a density of 22.4 g/cm33, and an , and an atomic weight of 50.9g/molatomic weight of 50.9g/mol

15

Problem 3.28

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

Since 0.732 < 0.939 < 1.0, cubic sites preferred

So each Cs+ has 8 neighbor Cl-

16

Problem 3.28

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

17

Problem 3.34

A hypothetical AX type of ceramic material is known to A hypothetical AX type of ceramic material is known to have a density of 2.65g/cmhave a density of 2.65g/cm33 and a unit cell of cubic and a unit cell of cubic symmetry with a cell edge length of 0.43nm. The atomic 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, weights of the A and X elements are 86.6 and 40.3g/mol, respectively. On the basis of this information, which of respectively. On the basis of this information, which of the following crystal structures is(are) possible for this the following crystal structures is(are) possible for this material: rock salt, cesium chloride, or zinc blende?material: rock salt, cesium chloride, or zinc blende?

CsCl and ZnSCsCl and ZnS