What is different in ionisation enthalpy in p block group???
Answers
Definition: It is the amount of energy required to remove the most loosely bound electron from the outermost shell of a neutral gaseous atom. It is measured in kJ/mol and is known as first ionization enthalpy.
The first Ionization Enthalpy of P-Block elements generally increases on moving from left to right along a period. It is because as we move from left to right along a period, the atomic size decreases. In a small atom, the electrons are held tightly. The larger the atom, the less strongly the electrons are held by the nucleus. The ionization enthalpy, therefore, increases with decrease in atomic size.
However, there are certain exceptions, e.g. The first ionization enthalpy of a group 16 elements (Chalkogens) is lower than that of group 15 elements (Pnictogens).
It is because in case of group 15 elements, the electron is to be removed from the half-filled p-orbitals.
In general, In P-Block elements, the first ionization enthalpy decreases in a regular way on a descending group. It is because on a descending group, the atomic size increases. As a result, the electrons are less tightly held by the nucleus and therefore, the first ionization enthalpy decreases.
I hope this would help you!!