حل اساله البلورات_030146.pdf

Write the scientific term for the following sentence 1- A finite array of points in three-diamensions in which every point has identical environment as any point in the array (crystal lattic) 2- An electromagnetic waves and their wavelength is expressed as 𝜆 = h C / E (x-ray)...

Write the scientific term for the following sentence 1- A finite array of points in three-diamensions in which every point has identical environment as any point in the array (crystal lattic) 2- An electromagnetic waves and their wavelength is expressed as 𝜆 = h C / E (x-ray) 3- The bonds are those in the alkalihalides such as sodium chloride NaCl (ionic bond) 4- Solid which are arranged in a regular order ( single crystal) 5- The minimum volume unit cell having only one lattice point (primitive unit cell) 6- The law that presented a simple explanation of the diffracted beams from a crystal (Braggs law) 7- A combination of vacancy and interstitial defects (frenkel) 8- An operation that take the crystal into itself (symmetry operation) 9- Operation include a n-fold rotation followed by an inversion ( roto-inversion) 10- Crystal system which has a= b≠ c , α=β=γ=90 (tetragonal) 11- The crystal system which have a≠B≠c , α=β=90≠γ ( monoclinic ) 12- Dislocation which can be easily visualized as a extra half plane of atoms in a lattice (Edge dislocation) 13- In a closed packed structure of atoms in a crystal of the atomic packing factor is low an extra atom may be lodge within the crystal structure ( interstitial defects ) 14- Chemical bonds involve the sharing of a pair of valance electrons by two atoms (covalent bond) 15- A bond which is formed in metals (metallic bond) 16- Solids occur when covalent molecules are held together by intermolecular forces(Molecular solids) 17- The combination of an n-fold rotation and a reflection at the plane ,perpendicular to the rotation axis (roto-reflection point symmetry operation) 18- An operation which is defined as the displacement of a crystal parallel to itself (translation operation) 19- A set of numbers which quantity the intercepts and thus may be used to uniquely identify the plane or surface ( Miller indices) 20- An operation combining an n-fold rotation with a transition parallel to the rotation axis (screw translation hybrid symmetry operations) 21- Method where the film is placed between the x-ray source and the crystal (Back reflection layer method) I  22- In one type of dislocations ,the Burger vector is perpendicular to the dislocation line (edge dislocation) 23- Solid are not arranged in a regular order (amorphous solid ) 24- An impurity atom at the regular or interstitial position in the lattice (interstitial imperfection) 25- Charged particles used in the analysis of crystal structure and interact strongly with all atoms (electrons (electron diffraction)) 26- A method which is useful for studying samples that are difficult to obtain in single crystal form (the power method) 27- A reflection with a transition parallel to the reflection plane (Glide reflaction) 28- The atomic arrangement in a crystal (crystal structure) 29- A cation vacancy and cation interstitial pair ( frenkel defect ) 30- Method is mainly used to determine the orientation of large single crystal (laue method) 31- A region of atomic disorder in the lattice only a few atomic diameters wide (Grain boundary ) 32- A region of localized lattice distortion which separates the slipped and unslipped portion of the crystal ( Dislocation ) 33- A cation vacancy – anion vacancy (schottky defect) Write yes or no and correct 1- The beam which uses in laue method is single beam No(polychromatic beam) 2- Bragging law presented a simple explanation of the diffracted beams from a crystal yes 3- Amorphous solids are not arranged in a regular order as are those in crystalline solids yes 4- Bragg reflection can occur only for wave length 𝜆 ≤ 2d yes 5- The Miller indices are enclosed within standard brackets (h,k,l) when one is specifying No( (hkl) ) 6- In oblique crystal system a≠B≠C , α= β= 90≠γ No II  (monoclinic) 7- Grains are formed during the soldification process yes 8- The screw dislocation can be easily visualized as an extra half plane of atoms in lattic No )edge dislocation ) 9- Typical of covalent bond are those in the alkalihalides such as NaCl No )ionic bond) 10- The unit cell and consequently the entire lattice ,is uniquely determined by only three lattic constant No (six ) 11- Combine a reflaction with a translation parallel to the reflection plane to achieve congruence in some Crystal's is called screw translation No )hybrid ) 12- Unit cell is the smallest unit of a crystal, which , if repeated , could generate the whole crystal yes 13- In the back-reflection powder diffraction method , the crystal is blacead between x- ray source and the film No(crystal) 14- In ionically bonded materials the ion must move past an area with a repulsive charge in order to get the next location of the same charge yes 15- Amorphous solid they are arranged in a regular order as are those in crystalline solids No( poly crystalline) 16- The motion of edge defect is also a result of sheer stress No( screw ) Choose the correct answer III 1- Which of these is a lattice type ( K – E – N –C ) 2- An impurity atom at the regular arranged the crystal ( vacancy defect –interstitial defect – schottky defect – frenkel defect ) 3- Which of the following interact with nuclei ( x-ray _Neutron _ electron) 4- The energy of the photon is given by the formula 2 2 )E=p/2m _E = Hv _ h /2m 𝜆 ) 5- The unit cell which have one and half lattice point called )Primitive unit cell _non-primitive unit cell _ space lattice) 6- How many Bravais lattices (2D) are there (3_ 4_5 _ 6) 7- A technique for grown single crystal which is the feed materials is taken in the form of sintered rod and the seed is attached to one end (zone melting _ Bridgman _ czochralski ) 8- How many mirror planes does this square shape has and draw them if there are ( zero _ one _ two _ four ) 9- How many mirror planes does this square shape has and draw if there are ( zero _one _ three _ five ) 10- How many mirror planes does this shape has and draw them if there are ( zero _ two _ three _six ) 11- How many mirror planes does this shape has and draw them if this are ( zero – one _two _ four ) IV 12- How many mirror planes does this shape has and draw them if this are (zero _ one _ two _ three) 13- This symmetry operations called ( reflection _ inversion _ rotation ) 14- How many bravais lattices in three dimensions (36 _28 _14 16 ) 15- How many bravais lattices (3D) are there (14 _ 4_5_6) 16- Solid which consists of positive cores of atoms held together by a surrounding sea of electrons (metallic solid _ molecular solid _ ionic solid ) 17- Hexagonal unit cell is …………unit cell (primitive _ non primitive _ body centered tetragonal) 18- The minimum volume unit cell having one lattice point (body center cubic _simple tetragonal _ non primitive unit cell) 19- Solid which are arranged in a regular order called ………..solid ( polycrystalline _ amorphous _ V  crystalline ) 20- Crystal system which has a≠ b ≠c and α≠ β≠γ ≠90 (triclinic _ tetragonal _ monoclinic ) 21- A symbolic vector representation for the orientation of an atomic plane in a crystal lattice ( inversion symmetry operation _ rotation symmetry operation _miller indices ) 22- A method which is useful for studying samples that are difficult to obtain in single crystal form ( laue method _ powder method _ rotating crystal method) 23- The electromagnetic waves with energy equal E = hv ( neutron_x-ray _ electron) 24- Method that used to determine the orientation of the single crystal ( powder method _laue method _ rotating crystal method ) 25- How many fold rotational symmetry does this shape has ? (Two _ zero _ one _ four) 26- This symmetry operations called …………. Of symmetry plane faces ( plane faces _diagonal planes _tetras axis ) VI 27- 28- -29 Write short note 1- X ray diffraction is a nondestructive technique which is used in different applications mention only four of its uses and it is advantages and disadvantages???? VII Type of uses: 1- Differentiation between crystalline and amorphous materials 2- Determination of the structure of crystalline materials 3- Determination of the orientation of single Crystal's 4- Determination of the texture of poly grained materials Advantages: Cheapest, the most convenient and widely used method Not absorbed very much by air Disadvantages : Not interact very strongly with lighter element 2- Explain with drawing the cubic system and calculate the number of atoms in each cubic unit cell ?? Simple cupic n = 8 × (1/8) = 1 atom Body centered cubic n = 8 × (1/8) +1 = 2 atom Face centered cubic n = 8 × (1/8) + 6 × (1/2) = 4 atom VIII  3- In screw translation hybrid symmetry operations, draw the six diagonal planes of symmetry in a cubic??? 4- Different type of crystalline solids and compare between them ?? 1- Molecular solid: consist of atoms or molecule are held together by intermolecular force like dry ice co2 2- Metallic solid:consist of positive cores of atoms are held together by surrounding sea of electrons like copper , iron 3- Ionic solid: consist of cations and anions held together by electrical attraction of positive charge like Nacl 4- Covalent solid: consist of atoms held together large net work or chains by covalent bond like diamond or graphite. Type of solid Melting point Hardness Electrical conductivity Molecular Low Soft Nonconducting Ionic Variable Malleable Conducting Metallic High to Very Hard Nonconducting high solid Conducting liquid Covalent Very high Very hard Usually nonconducting IX  5- Compare between amorphous and crystalline and poly crystalline solids. Crystalline Amorphous Polycrystalline or grains Arranged in Not arranged Have a high regular order in a regular degree of order order over many atomic Have a Solid are made Grains: periodic up of separated by structure a randomly grain boundry cross it's orientation whole volume atoms, icons or molecules 6- Explain the lattice parameter of the unit cell which used to describe the crystal??  In describing crystal structure, it often convenient to subdivide the structure into small repeat entities called unit cell  The unit cell is the basic structural unit or building block of the crystal structure by virtue of its geometry and atomic position within. X  7- The basis and crystal structure???  Crystal structure can be obtained by attaching atoms, group of atoms or molecule which are called basis to the lattice sides of the lattice point.  Basis: a unit assembly of atoms or molecules identical in composition.  Crystal structure: the atomic arrangement in a crystal.  Basis+ crystal lattice = crystal structure  Crystal lattice: an infinite array of points in space. 8- Different type of point defect and explain two of them?? 1- Frenkel defect 2- Schottky defect 3- Vacancy 4- Interstitial defect Schottky defect: a cation vacancy – anion vacancy pair Frenkel defect: a cation vacancy and a cation interstitial pair 9- Explain with drawing the different types of symmetry point operations?? 1- Inversion 2- Mirror XI -3 Rotation XII