Test 1

1、单选题：
Atomic weight (A) of an element corresponds to the weighted average of the atomic masses of the atom’s naturally occurring ___________.‌‍‌
选项：
A: ions
B: charges
C: isotopes 
D: particles
答案: 【 isotopes 】

2、单选题：
Which of the following is NOT an example of primary bonding?‍‌‍
选项：
A: Van der Waals
B: ionic
C: covalent
D: metallic
答案: 【 Van der Waals】

3、单选题：
​Covalent bonding occurs as a result of _________ sharing.‎​‎
选项：
A: proton
B: electron
C: neutron
D: none of them
答案: 【 electron】

4、单选题：
Bonds in most metals are referred to as ______.‎‎‎
选项：
A: Directional
B: Ionic
C: Non-directional
D: Covalent
答案: 【 Non-directional】

5、单选题：
‍If the electron configuration of Fe is 1s2 2s2 2p6 3s2 3p6 3d6 4s2, then the electron configurations for the Fe3+ is 1s2 2s2 2p6 3s2 _____.‍‍‍
选项：
A: 3p6 3d5
B: 3p8 3d3
C: 3d6 3p5
D: 3d6 4s2 4p3
答案: 【 3p6 3d5】

Test 2

1、单选题：
How many atoms does the face centered cubic unit cell contain?‌‍‌
选项：
A: Two 
B: Four 
C:  Three
D: One
答案: 【 Four 】

2、单选题：
The crystal structure of Cu is          ?‌‎‌
选项：
A: Simple cubic
B: FCC 
C:  BCC
D: HCP
答案: 【 FCC 】

3、单选题：
The coordination number of BCC crystal structure is               .‌‌‎‌
选项：
A: 2
B: 4
C: 6
D: 8
答案: 【 8】

4、单选题：
The atomic packing factor for FCC is                  .‌‌‍‌
选项：
A: 0.74 
B: 0.68
C:  0.8
D:  1
答案: 【 0.74 】

5、单选题：
Interstitial solid solution belongs to                       .‍‍​‍
选项：
A: infinite solid solution; 
B: finite solid solution;
C: unhomogeneous solid solution ;
D: substitutional solid solution
答案: 【 finite solid solution; 】

6、单选题：
Substitutional atom (impurity) is an example of ______.‏‏‏‌‏
选项：
A: point defect 
B: linear defect
C: planar defect
D: bulk defect
答案: 【 point defect 】

7、单选题：
One explanation for why graphite powder acts so well as a “solid lubricant”is               .‏‍‏
选项：
A: carbon atoms in graphite are covalently bonded within planar layers but have weaker secondary bonds between layers
B: