Converting binding energy of an element to joules!! The binding energy of Mg-24 is 198MeV. What is this value in Joules? Write your answer correct to three significant figures. MeV = megaelectron volt 1 megaelectron volt = 1.60217646 × 10-13 joules 198 megaelectron volts = 3.17230939 × 10^-11 joules 198 megaelectron volts = 3.17230939 × 10^-11 joules So, the answer should be 3.17E-11. Correct? I got the answer wrong on the homework... Could it be because I didn't add the unit to the end of the answer? Or am I just completely wrong?