Question 18: What are the various factors due to which the ionization enthalpy of the main group elements tends to decrease down a group?
Answer:
The minimum amount of energy which is needed to remove the most loosely bound electron from a neutral isolated atom to form a cation is called as ionization energy or enthalpy.
The factors responsible for the ionization enthalpy of the main group elements to decrease down a group are listed below:
(i) Increase in the atomic size of elements: As we move down a group, the number of main energy shells(n) increases. As a result, the atomic size also increases gradually on moving down a group. As the distance of the valence electrons from the nucleus increases, the electrons are not held very strongly. Thus, they can be removed easily. Hence, on moving down a group, ionization energy decreases.
(ii) Increase in the shielding effect: The number of inner shells of electrons increases on moving down a group. Therefore, the shielding of the valence electrons from the nucleus by the inner core electrons increases down a group. As a result, the valence electrons are not held very tightly by the nucleus. Hence, the energy required to remove a valence electron decreases down a group.
Comments
Lovely answer
Superb explanation.....
Loved this! Tysm for your perfect answers!
Thnq very much
Thanks it is very useful
awesome site made by them
i have not seen such a site like this which has knowledge of everything and it is free accessible unlike other sites like Meritnation,toppers,etc. Very useful Thank You
Thankss.... Very Useful
Extremely helpful site.
Thanks for making this website! It's super helpful :)