Sodium metal crystallises in a body centred cubic lattice with a unit cell edge of 4.29 Å . The radius of sodium atom is

Step-by-step solution

For a body-centred cubic (BCC) lattice, the relationship between the unit cell edge length a and the atomic radius r is given by the formula: 3 a = 4r Given the unit cell edge length a = 4.29 Å , we substitute this value into the formula: r = 3 a 4 r = 1.732 4.29 4 r = 7.42928 4 r = 1.85732 Å Rounding to two decimal places, we get r 1.86 Å . Answer: 1.86 Å