Electromagnetic radiation of wavelength 286 nm is just sufficient to ionise the sodium atom. Calculate the ionisation energy in kJ/mol.(Planck's constant (h) = 6.626×10−34Js)
A
418.8kJmol−1
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
B
209.4kJmol−1
No worries! We‘ve got your back. Try BYJU‘S free classes today!
C
41.8kJmol−1
No worries! We‘ve got your back. Try BYJU‘S free classes today!
D
814.2kJmol−1
No worries! We‘ve got your back. Try BYJU‘S free classes today!
Open in App
Solution
The correct option is A418.8kJmol−1 λ=242nm=242×10−9mc=3×108ms−1E=hv=hcλ=6.626×10−34×3×108242×10−9=0.082×10−17J=0.082×10−20kJEnergy per mole for ionisation =0.082×10−20×6.022×1023=493.6kJmol−1