Why does the first ionization enthalpy increase as we go . from left to right across a given period of the Periodic Table?
The value of ionization enthalpy increases with the increase in atomic number across the period. This is due to the fact that in moving across the period from left to right., Nuclear charge increases regularly by one unit. The progressive addition of electrons occurs at the same level. Atomic size decreases. This is due to the gradual increase in nuclear charge and a simultaneous decrease in atomic size the electrons are more and more tightly bound to the nucleus. This results in a gradual increase in ionization energy across the period.
