SSC MTS EXAM

Detailed explanation-1: -First ionization energy is the energy that is required to remove the first electron from a neutral atom. It is numerically same as the orbital energy of the electron but of opposite sign.

Detailed explanation-2: -The energy required to remove an electron from an atom in gaseous state is called as ionization enthalpy.

Detailed explanation-3: -The first ionization energy is the energy required to remove the most loosely held electron from one mole of neutral gaseous atoms to produce 1 mole of gaseous ions each with a charge of 1+. This is more easily seen in symbol terms. It is the energy needed to carry out this change per mole of X.