NEET 2022 | Structure of an Atom | Parmanu Ki Sanrachna One Shot | All Concepts, Tricks & PYQs

A compound AB has zinc blende structure with Aatoms at corners and face centre of the unit cell.If all the atoms present in one body diagonal are removed,the formula of the compound becomes A_(x)B_(y) .The sum (x+y) is

All real structures are three dimensional structures. They can be obtained by stacking two dimensional layers one above the other while placing the second square dose packed layer above the first we follow the same rule that was followed when one row was placed adjacent to the other. The second layer is placed over the first layer such that the spheres of the upper layer are exactly above there of the first layer. In his arrangement spheres of both the layers are perfectly aligned horizontally as well as vertically. A metallic element crystallise into a lattice having a ABC ABC pattern and packing of spheres leaves out voids in the lattice. What is the total volume of atoms in a face centred cubic unit cell of a metal? (r is atomic radius).

In a solid 'AB' having rock salt arrangement ( NaCl structure), 'A' atoms occupy the corners and face center of the cubic unit cell. 'B' atoms occupies all octahedral voids of the unit cell. If all the face - centered atoms along one of the axes are removed, then the resultant stoichiometry of the solid is

In a solid having rock salt structure, if all tge atoms touching one body diagonal plane are removed (except at body centre), then the formula of the left unit cell is

Early crystallographers had trouble solving the structures of inorganic solids using X-ray diffraction because some of the mathematical tools for analyzing the data had not yet been developed. Once a trial structure was proposed, it was relatively easy to calculate the diffraction pattern, but it was difficult to go the other way (from the diffraction pattern to the structure) if nothing was known a priori about the arrangement of atoms in the unit cell. It was important to develop some guidelines for guessing the coordination numbers and bonding geometries of atoms in crystals. The first such rules were proposed by Linus Pauling, who considered how one might pack together oppositely charged spheres of different radii. Pauling proposed from geometric considerations that the quality of the "fit" depended on the radius ratio of the anion and the cation. If the anion is considered as the packing atom in the crystal, then the smaller cation fills interstitial sites ("holes"). Cations will find arrangements in which they can contact the largest number of anions. If the cation can touch all of its nearest neighbour anions then the fit is good. If the cation is too small for a given site, that coordination number will be unstable and it will prefer a lower coordination structure. The table below gives the ranges of cation/anion radius ratios that give the best fit for a given coordination geometry. A "good fit" is considered to be one where the cation can touch:

Early crystallographers had trouble solving the structures of inorganic solids using X-ray diffraction because some of the mathematical tools for analyzing the data had not yet been developed. Once a trial structure was proposed, it was relatively easy to calculate the diffraction pattern, but it was difficult to go the other way (from the diffraction pattern to the structure) if nothing was known a priori about the arrangement of atoms in the unit cell. It was important to develop some guidelines for guessing the coordination numbers and bonding geometries of atoms in crystals. The first such rules were proposed by Linus Pauling, who considered how one might pack together oppositely charged spheres of different radii. Pauling proposed from geometric considerations that the quality of the "fit" depended on the radius ratio of the anion and the cation. If the anion is considered as the packing atom in the crystal, then the smaller cation fills interstitial sites ("holes"). Cations will find arrangements in which they can contact the largest number of anions. If the cation can touch all of its nearest neighbour anions then the fit is good. If the cation is too small for a given site, that coordination number will be unstable and it will prefer a lower coordination structure. The table below gives the ranges of cation/anion radius ratios that give the best fit for a given coordination geometry. A solid AB has square planar structure. If the radius of cation A^+ is 120pm,Calculate the maximum possible value of anion B^-

Early crystallographers had trouble solving the structures of inorganic solids using X-ray diffraction because some of the mathematical tools for analyzing the data had not yet been developed. Once a trial structure was proposed, it was relatively easy to calculate the diffraction pattern, but it was difficult to go the other way (from the diffraction pattern to the structure) if nothing was known a priori about the arrangement of atoms in the unit cell. It was important to develop some guidelines for guessing the coordination numbers and bonding geometries of atoms in crystals. The first such rules were proposed by Linus Pauling, who considered how one might pack together oppositely charged spheres of different radii. Pauling proposed from geometric considerations that the quality of the "fit" depended on the radius ratio of the anion and the cation. If the anion is considered as the packing atom in the crystal, then the smaller cation fills interstitial sites ("holes"). Cations will find arrangements in which they can contact the largest number of anions. If the cation can touch all of its nearest neighbour anions then the fit is good. If the cation is too small for a given site, that coordination number will be unstable and it will prefer a lower coordination structure. The table below gives the ranges of cation/anion radius ratios that give the best fit for a given coordination geometry. The radius of Ag^+ ion is 126pm and of I^- ion is 216pm. The coordination number of Ag^+ ion is:

Early crystallographers had trouble solving the structures of inorganic solids using X-ray diffraction because some of the mathematical tools for analyzing the data had not yet been developed. Once a trial structure was proposed, it was relatively easy to calculate the diffraction pattern, but it was difficult to go the other way (from the diffraction pattern to the structure) if nothing was known a priori about the arrangement of atoms in the unit cell. It was important to develop some guidelines for guessing the coordination numbers and bonding geometries of atoms in crystals. The first such rules were proposed by Linus Pauling, who considered how one might pack together oppositely charged spheres of different radii. Pauling proposed from geometric considerations that the quality of the "fit" depended on the radius ratio of the anion and the cation. If the anion is considered as the packing atom in the crystal, then the smaller catin fills interstitial sites ("holes"). Cations will find arrangements in which they can contact the largest number of anions. If the cation can touch all of its nearest neighbour anions then the fit is good. If the cation is too small for a given site, that coordination number will be unstable and it will prefer a lower coordination structure. The table below gives the ranges of cation/anion radius ratios that give the best fit for a given coordination geometry. {:("Coordiantion number","Geometry",rho =(r_("cation"))/(r_("amion"))),(2,"linear",0-0.155),(3,"triangular",0.155 - 0.225),(4,"tetrahedral",0.225 - 0.414),(4,"square planar",0.414 - 0.732),(6,"octahedral",0.414 - 0.732),(8,"cubic",0.732 - 1.0),(12,"cuboctahedral",1.0):} (Source : Ionic Radii and Radius Ratios. (2021, June 8). Retrieved June 29, 2021, from https://chem.ibretexts.org/@go/page/183346) A solid AB has square planar structure. If the radius of cation A^(+) is 120 pm, calculate the maximum possible value of anion B^(-) .

Early crystallographers had trouble solving the structures of inorganic solids using X-ray diffraction because some of the mathematical tools for analyzing the data had not yet been developed. Once a trial structure was proposed, it was relatively easy to calculate the diffraction pattern, but it was difficult to go the other way (from the diffraction pattern to the structure) if nothing was known a priori about the arrangement of atoms in the unit cell. It was important to develop some guidelines for guessing the coordination numbers and bonding geometries of atoms in crystals. The first such rules were proposed by Linus Pauling, who considered how one might pack together oppositely charged spheres of different radii. Pauling proposed from geometric considerations that the quality of the "fit" depended on the radius ratio of the anion and the cation. If the anion is considered as the packing atom in the crystal, then the smaller catin fills interstitial sites ("holes"). Cations will find arrangements in which they can contact the largest number of anions. If the cation can touch all of its nearest neighbour anions then the fit is good. If the cation is too small for a given site, that coordination number will be unstable and it will prefer a lower coordination structure. The table below gives the ranges of cation/anion radius ratios that give the best fit for a given coordination geometry. {:("Coordiantion number","Geometry",rho =(r_("cation"))/(r_("amion"))),(2,"linear",0-0.155),(3,"triangular",0.155 - 0.225),(4,"tetrahedral",0.225 - 0.414),(4,"square planar",0.414 - 0.732),(6,"octahedral",0.414 - 0.732),(8,"cubic",0.732 - 1.0),(12,"cuboctahedral",1.0):} (Source : Ionic Radii and Radius Ratios. (2021, June 8). Retrieved June 29, 2021, from https://chem.ibretexts.org/@go/page/183346) The radius of Ag^(+) ion is 126 pm and of I^(-) ion is 216 pm. The coordination number of Ag^(+) ion is :

Phosphorus forms a number of oxoacids which differ in their structures and oxidation state of phosphorus. All the acids contain phosphorus atom//atoms linked tetrahedrally to four other atoms or groups. Each of them has at least one P=O or P rarr O unit and one P-OH unit. The OH group is ionisable but H atom linked directly to P is non-ionisabl. Structures of all the acids are considered to be derived either from phosphorus acid or phosphoric acid. Which one is monobasic acid ?