how can we calculate first ionization energy of an element?or does ionization energy will be given in exams?
The ionization energy of a chemical species (i.e.,an atom or molecule) is the energy required to remove electrons from gaseous atoms or ions. The property is alternately still often called the ionization potential, measured in volts. In chemistry it often refers to one mole of a substance (molar ionization energy or enthalpy) and reported in kJ/mol. In atomic physics the ionization energy is typically measured in the unit electron volt (eV). You can calculate it,but it is more physical problem and not chemical. Usually this tabular value given in the description of the task.