Question

The magnesium atom has an ionization energy of 737.7 kJ mol. What is the longest wavelength of light that could ionize a magnesium atom? In which region of the electromagnetic spectrum does this light fall? Wavelength = Region Submit Answer 5 question attempts remaining

Answer 1

1)
Given:
Energy of 1 mol = 7.377*10^2 KJ/mol
= 7.377*10^5 J/mol
Find energy of 1 photon first
Energy of 1 photon = energy of 1 mol/Avogadro's number
= 7.377*10^5/(6.022*10^23)
= 1.225*10^-18 J
This is energy of 1 photon

use:
E = h*c/lambda
1.225*10^-18J =(6.626*10^-34 J.s)*(3.0*10^8 m/s)/lambda
lambda = 1.623*10^-7 m
lambda = 162 nm
Answer: 162 nm

2)
162 nm lies in ultraviolet region
Answer: ultraviolet