In the following questions, statement is followed by statement II. Each question has the following four choices out of which only one is correct.

Statement I: Generally, ionization enthalpy increases from left to right in a period.
Statement II: When successive electrons are added to the orbitals in the same principal quantum level, the shielding effect of inner electrons (core of electrons) does not increase very much to compensate for increased attraction of the electron to the nucleus.