JEE Main20264 April 2026Evening ShiftChemistryClassification of Elements and Periodicity in PropertiesActual
The 1^ st ionization enthalpy for Mg is +737 kJ/mol. The most probable estimated value of the 2^ nd ionization enthalpy of Mg is ______.
Options
- A-906 kJ/mol
- B-856 kJ/mol
- C+1450 kJ/mol
- D+590 kJ/mol
Correct answer
C. +1450 kJ/mol
Step-by-step solution
Ionization enthalpy is the energy required to remove an electron from an isolated gaseous atom or ion. It is always an endothermic process, so its value is always positive. The second ionization enthalpy is the energy required to remove an electron from a unipositive ion. Since the effective nuclear charge increases after the removal of the first electron, the remaining electrons are held more tightly by the nucleus. Thus, the second ionization enthalpy is always greater than the first ionization enthalpy ( IE₂ > I