NTA Abhyas JEE Main2020ChemistrySolid StatePractice
The number of unit cells present in 39 g of potassium if it crystallizes as body centred cube is ( N = Avogadro number, At. Wt. of potassium = 39 g/mol )
Options
- AN 4
- BN 2
- CN 3
- DN
Correct answer
B. N 2
Step-by-step solution
Potassium has bcc system Number of mole = 39/39 = 1 mole 1 mole of atoms = 6 .022 × 10 23 atoms = N ∵ In bcc system 2 atoms are present in 1 unit cell. ∴   N number of atoms are present in N 2 unit cells.