材料科学基础习题与答案
B.共价键
C.金属键
D.等量的离子键和共价键
E.等量的金属键和共价键
B.离子键、金属键
C.共价键、离子键、分子键、金属键
D.金属键、范德华力
B.离子键、金属键
C.共价键、离子键、分子键、金属键
D.金属键、范德华力
石墨晶体中,层与层之问的结合力可能是()。
- A、金属键
- B、共价键
- C、范德华力
- D、离子键
正确答案:C
说明离子键、共价键、分子键和金属键的特点。
正确答案:离子键、共价键、分子键和金属键都是指固体中原子(离子或分子)间结合方式或作用力。离子键是由电离能很小、易失去电子的金属原子与电子亲合能大的非金属原于相互作用时,产生电子得失而形成的离子固体的结合方式。
共价键是由相邻原子共有其价电子来获得稳态电子结构的结合方式。
分子键是由分子(或原子)中电荷的极化现象所产生的弱引力结合的结合方式。
当大量金属原子的价电子脱离所属原子而形成自由电子时,由金属的正离子与自由电子间的静电引力使金属原子结合起来的方式为金属键。
摘要:第二章思考题与例题1.离子键、共价键、分子键和金属键的特点,并解释金属键结合的固体材料的密度比离子键或共价键固体高的原因?2.从结构、性能等方面描述晶体与非晶体的区别。3.何谓理想晶体?何谓单晶、多晶、晶粒及亚晶?为什么单晶体成各向异性而多晶体一般情况下不显示各向异性?何谓空间点阵、晶体结构及晶胞?晶胞有哪些重要的特征参数?4.比较三种典型晶体结构的特征。(Al、α-Fe、Mg三种材料属何种晶体结构?描述它们的晶体结构特征并比较它们塑性的好坏并解释。)何谓配位数?何谓致密度?金属中常见的三种晶体结构从原子排列紧密程度等方面比较有何异同?5.固溶体和中间相的类型、特点和性能。何谓间隙固溶体?它与间隙相、间隙化合物之间有何区别?(以金属为基的)固溶体与中间相的主要差异(如结构、键性、性能)是什么?6.已知Cu的原子直径为2.56,求Cu的晶格常数,并计算1mm3Cu的原子数。7.已知Al相对原子质量Ar(Al)=26.97,原子半径γ=0.143nm,求Al晶体的密度。8bcc铁的单位晶胞体积,在912℃时是0.02464nm3;fcc铁在相同温度时其单位晶胞体积是0.0486nm3。当铁由bcc转变为fcc时,其密度改变的百分比为多少?9.何谓金属化合物?常见金属化合物有几类?影响它们形成和结构的主要因素是什么?其性能如何?10.在面心立方晶胞中画出[012]和[13]晶向。在面心立方晶胞中画出(012)和(13)晶面。11.设晶面(152)和(034)属六方晶系的正交坐标表述,试给出其四轴坐标的表示。反之,求()及(22)的正交坐标的表示。(练习),上题
锗晶体和硅晶体外围有四个电子,可形成()。
- A、共价键
- B、金属键
- C、离子键
- D、氢键
正确答案:A
金属键、离子键、共价键及分子键结合的材料其性能有何特点?
正确答案:金属键:大量自由电子,良好导电导热性,又因金属键的饱和性无方向性,结构高度对,故有良好的延展性。
离子键:正负离子的较强电吸引,导致高硬度,高熔点,高脆性,因无自由电子,固态导电性差。
共价键:通过共用电子对实现搭桥联系,键能高,高硬度,高熔点,高介电性。
分子键:因其结合键能低,低熔点,低强度,高柔顺性。
钻石晶体结构中化学键类型是()。
- A、分子键
- B、离子键
- C、共价键
- D、金属键
正确答案:C
金属晶体是通过()相结合在一起的。
- A、配位键
- B、共价键
- C、离子键
- D、金属键
正确答案:D
金属原子的结合方式是()。
- A、离子键
- B、共价键
- C、金属键
- D、分子键
正确答案:C
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