Question

if three elements p,q and r crystallize in a cubic solid lattice with p atoms at the corners, q atoms at the cube centre and r atoms at the centre of the faces of the cube, then write the formula of the compound

Answer 1

P is at corners thus 1/8×8=1

Q is at cube centre thus 1

and

R is at centre of the faces thus 1/8×8 + 1/6×2= 4

Thus the answer will be PQR4

Answer 2

Answer: contribution made by the atoms p present at all the eight corners of the cube 1/8*8= 1

Contribution made by atoms of Q present in the centre of the body = 1

Contribution made by the atoms of R present at the centre of all the six faces 1/2*6= 3

Therefore the formulat of the compound PQR3

Explanation: