Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
JEE MainChemistrySolid State

A cubic crystalline solid consists of elements A and B. Atoms of A occupy all the corners of the cubic unit cell, while atoms of B occupy the face centers. However, some B atoms are missing from their designated face center sites. If the empirical formula of the compound is AB _ 2.5 , the number of missing B atoms per unit cell is

Options

  1. A5
  2. B2
  3. C1
  4. D3

Correct answer

C. 1

Step-by-step solution

The effective number of A atoms per unit cell is calculated from the atoms at the corners. Number of A atoms = 8 1 8 = 1 Since the empirical formula is AB _ 2.5 and the number of A atoms is 1, the effective number of B atoms per unit cell must be 2.5. Let the number of occupied face centers be x . The contribution of an atom at a face center is 1 2 . x 1 2 = 2.5 x = 5 A cubic unit cell has 6 face centers in total. Therefore, the number of missing B atoms is 6 - 5 = 1 . Answer: 1

Practice Solid State on Quantrex Academy →

More from Solid State

The density (in g cm ⁻³ ) of the metal which forms a cubic close packed (ccp) lattice with an axial distance (edge length) equal to 400 pm is . Use: Atomic mass of metal =105.6 amu 2025Atoms of metals x , y and z form face-centred cubic (fcc) unit cell of edge length L x , body-centred cubic (bcc) unit cell of edge length L y , and simple cubic unit cell of edge 2023Which of the following expressions is correct in case of a CsCl unit cell (edge length ‘ a ’) ? 2023Sodium metal crystallises in a body centred cubic lattice with unit cell edge length of 4 Å . The radius of sodium atom is _ _ _ × 10 - 1 Å . (Nearest integer) 2023An atomic substance A of molar mass 12 g mol – 1 has a cubic crystal structure with edge length of 300 pm . The no. of atoms present in one unit cell of A is (Nearest integer 2023The correct relationships between unit cell edge length ‘ a ’ and radius of sphere ‘ r ’ for face-centred and body-centred cubic structures respectively are 2023Number of crystal systems from the following where body centred unit cell can be found, is _____. Cubic, tetragonal, orthorhombic, hexagonal, rhombohedral, monoclinic, triclinic 2023A compound is formed by two elements X and Y . The element Y forms cubic close packed arrangement and those of element X occupy one third of the tetrahedral voids. What is the form 2023 Full Solid State list All JEE Main PYQs