Verified Solution • 2025–26 Session moderate

QJEEM15Cha25b: JEE Main 2015 Chemistry - Class 12 JEEM15Cha25b Solution: Sodium metal crystallizes in a body centred cubic lattice with…

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

Multiple Choice Options

  • A 5.72 Å
  • B 0.93 Å
  • C 1.86 Å
  • D 3.22 Å

Step-by-Step Verified Solution

In bccbcc the atoms touch along body diagonal

∴\therefore 2r+2r=3a2r + 2r = \sqrt 3 a

∴\therefore r=3a4=3×4.294=1.857A∘r = {{\sqrt 3 a} \over 4} = {{\sqrt 3 \times 4.29} \over 4} = 1.857\mathop A\limits^ \circ

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