In a face centred cubic arrangement of A & B atoms whose A atoms a...
Explanation:
Given:
- Face-centred cubic arrangement of A and B atoms
- A atoms at corner of unit cell
- B atoms at face centres
- One A atom missing from one corner
To find:
- Simplest formula of compound
Solution:
Step 1: Determine the number of A atoms in one unit cell
- A atoms are at the corner of the unit cell
- Each corner atom is shared between 8 unit cells
- Therefore, each corner atom contributes 1/8th of its atom to the unit cell
- There are 8 corner atoms in a unit cell
- Therefore, the total contribution of A atoms in one unit cell is 8 x 1/8 = 1 A atom
Step 2: Determine the number of B atoms in one unit cell
- B atoms are at the face centres
- Each face-centred atom is shared between 2 unit cells
- Therefore, each face-centred atom contributes 1/2 of its atom to the unit cell
- There are 6 face-centred atoms in a unit cell
- Therefore, the total contribution of B atoms in one unit cell is 6 x 1/2 = 3 B atoms
Step 3: Determine the simplest formula of the compound
- The ratio of A to B atoms in the compound is 1:3
- The formula of the compound is A1B3
- However, one A atom is missing from one corner in the unit cell
- Therefore, the formula of the compound becomes A7B24
Answer: The simplest formula of the compound is A7B24.
In a face centred cubic arrangement of A & B atoms whose A atoms a...
Here it's clear answer(c) is correct because we know contribution of corners in a cube is 1/8 and there are 8 corners in a cube now for FCC the contribution of face is 1/2 and there are 6 cube , later one corner is removed then contribution of corner atom =1/8*7= 7/8 and face is = 1/2*6=3 then formula = A7/8 B 3 we know formula is in simple ratio so we multiply 8 in both A and B then formula= A7B24 answer thank you Aj