NCERT Solutions for Class 12th Chemistry Chapter 1 The Solid State. Answer (i) The number of nearest neighbours of any constituent particle present in the crystal lattice is called its coordination number. Subscribe RSS Feed Pinterest Google Plus AglaSem Home»» schools.8/31/ caite.info - No.1 online tutoring company in India provides you Free PDF download of NCERT Solutions for Class 12 Chemistry Chapter 1 - The Solid State. Class XII. Chapter 1 – The Solid State. Chemistry. Page 1 of 34 What makes a glass different from a solid such as quartz? Under what conditions could.
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arrangement of the constituent particles, the two types of solids differ in their properties. General. Characteristics of Solid State. Amorphous. Amorphous. caite.info (Visit for all ncert solutions in text and videos, CBSE syllabus, note and many more). Chemistry Notes for class 12 Chapter 1 The. Solid State. National Council of Educational Research and Training (NCERT) Book for Class XII Subject: Chemistry Chapter: Chapter 1 – The Solid State. After studying this.
Properties of crystalline solids: Related titles. Here, the spheres of the second row ware placed exactly above those of the first row. This type of defect is created when some constituent particles atoms or molecules occupy an interstitial site of the crystal. When Si or Ge is doped with P or As. From equations iii and iv , we can determine the atomic mass of the unknown metal.
They have definite mass, volume and shape. They are compressible and rigid.
Intermolecular distances are very short and hence the intermolecular forces are strong. Their constituent particles have fixed position.
Classification of on the basis of the arrangement of constituent particles: Properties of crystalline solids: They have a definite geometrical shape.
They have a long range order. They have a sharp melting point.
They are anisotropic in nature i. They have a definite and characteristic heat of fusion. They are called true solids. When cut with a sharp edged tool , they split into two pieces and the newly generated surfaces are plain and smooth.
Polymorphic forms or polymorphs: Characteristics of amorphous solids: They have an irregular shape. They have a short range order. They gradually soften over arrange of temperature. They are isotropic in nature i. When cut with a sharp edged tool, they cut into two pieces with irregular surfaces.
They do not have definite heat of fusion. They are called pseudo solids or super cooled liquids. This is because they have a tendency to flow,though very slowly.
Types of crystalline solids: Molecular Solids Constituent Particles: Molecules Constituent Particles: Ions B. Fe ,Cu, Ag, Mg D. A regular ordered arrangement of constituent particles in three dimensions is called crystal lattice. Lattice points or lattice sites: A group of lattice points which when repeated over and over againin3dimensions give the complete crystal lattice.
Unit cell: It is defined as the smallest repeating unit in space lattice which when repeated over and over again generates the complete crystal lattice.
The crystal can consist of an infinite number of unit cells. Parameters which characterize a unit cel l: Dimensions of the unit cell along the three edges ,a, b and c: Inclination of the edges to each other: Seven crystal systems: Primitive or simple unit cells have constituent particles only at its corners. Centered unit cells are those unit cells in which one or more constituent particles are present at positions in addition to those present at the corners.
Types of centered unit cell s: Face centered unit cell: It consists of one constituent particle present at the centre of each face in addition to those present at the corners. Body centered unit cell: It consists of a one constituent particle is present at its body centre in addition to those present at the corners.
End centered unit cell: It consists of one constituent particle present at the centre of any two opposite faces in addition to those present at the corners. Number of particles at different lattice positions: Face centre: So, only half of the atom actually belongs to the unit cell. Body centre: So,that one atom completely belongs to the same unit cell.
End centre: So, only one fourth of an atom belongs to the unit cell. Number of atoms in different unit cells: Primitive unit cell have 1atom Face centered unit cell have 3 atoms Body centered unit cell have 2atoms Coordination number: Coordination number is the number of nearest neighbours of a particle.
Close packed structures: Close packing in two dimensions: It is generated by stacking the rows of close packed spheres in two ways: Close packing in three dimensions: They can be obtained by stacking the two dimensional layers one above the other. It can be obtained in two ways: Square close packing: Here, the spheres of the second row ware placed exactly above those of the first row.
This way the spheres are aligned horizontally as well as vertically. The arrangement is AAA type. The coordination number is 4. Hexagonal close packing: Here, these spheres of these bond row are placed above the first one in as taggered manner in such a way that its spheres fit in the depression of the first row.
The arrangement is ABAB type. The coordination number is 6. Three dimensional close packing from two dimensional square close packed layers: Here , the spheres of the upper layer are placed exactly over the first layer such the spheres of the layers are perfectly aligned horizontally and vertically.
It has a AAAA type pattern. The lattice is simple cubic lattice. Three dimensional close packing from two dimensional hexagonal close packed layers: There are two steps involved as: Covering the octahedral voids: Here, octahedral voids of these bond layer may be covered by the spheres of the third layer.
The three dimensional structure is called cubic close packed structure or face centered cubic structure. The coordination number is Cu, Ag.
Types of voids: Octahedral void- It is formed at the centre when six spheres are joined in the form of an octahedron. In hexagonal close packing or cubic close packing arrangement, the octa hedral and tetrahedral voids are present. The number of octahedral voids present in a lattice is equal to the number of close packed particles.
The number of tetrahedral voids is twice the number of octahedral voids. It is the percentage of total space occupied by constituent particles atoms, molecules orions.
For an atom to occupy an octahedral void, its radius must be 0. Radius ratio for tetrahedral void: For an atom to occupy a tetrahedral void, its radius must be 0. Density of a unit cell is same as the density of the substance. Relationship between radius of constituent particle r and edge length a: Simple cubic unit cell: Download Question Papers with solutions for Class Download Sample Papers with solutions for Class 12 Chemistry, Worksheets Access latest Worksheets, test papers, class test sheets for Class 12 Chemistry with important questions and answers for all topics and chapters as Download latest curriculum for Class 12 Chemistry with important Concepts Concepts, short notes, brief explanation, chapter summary for Class 12 Chemistry for all important topics of all chapters in Chemistry book for Class High Order Also download collection of Free download Since the board exams for both class 10 and class 12 has started, the CBSE board has instructed the parents and the students to follow some guidelines to sensify against the forged news spread through the social media platforms.
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