The density of Na is 0.613 ~g ~cm ⁻³ . If the edge length of unit cell of Na is 5 Å , the effective number of atoms of Na per unit cell is (Atomic weight of Na =23 u )

Step-by-step solution

We know that, d= Z m a^3 N_A where, d is density, Z is the number of atoms, m is the atomic mass, a is edge length and N_A is Avagadro's number. aligned Z & = d a^3 N_A m & = 0.613 ~g ~cm ⁻³ (5 10⁻⁸ ~cm )^3 6.023 10²³ 23 ~g =2 aligned