Question

. In a hypothetical crystal, each corner of a
cube is occupied by oxygen, each edge of the
cube is occupied by sodium and centre of the
cube is occupied by tungsten (W). Formula of
the crystal compound is
(1) NazW04 (2) Na3WO
(3) Na3W03 (4) NazWO3​

Answer 1

answer : option (2) Na3WO

explanation : each corner of the cube is occupied by oxygen.

so, number of oxygen atoms in cube = number of corners × 1/8 [ corner atom is shared by eight atoms.]

= 8 × 1/8 = 1

each edge of the cube is occupied by sodium.

so, number of sodium atoms in cube = number of edges × 1/4 [ edge atom is shared by 4 atoms. ]

= 12 × 1/4 = 3

and centre of the cube is occupied by Tungsten.

so, number of tungsten atom in cube = 1

ratio of atoms in cube :

Na : W : O = 3 : 1 : 1

now, formula of compound will be .... $Na_3WO$