Why ionisation enthalpy decreases down the group?

1.	Why ionisation enthalpy decreases down the group?
Answer» Because atomic radius increase<br>The amount of energy required to remove the outermost electron from an isolated, neutral gaseous atom to form a cation is known as ionisation energy.Ionisation energy decreases as we proceed down the group. This is because the size of the atom increases as we move down the group, and therefore the attraction between the nucleus and the outermost electron decreases. Because of this, it becomes easier for atom to lose the valence electrons. For example, the ionisation energy of potassium is more than that of sodium. Ionisation energy increases as we move from left to right across a period. Thus the ionisation energy of carbon is more than that of lithium.<br>*Skip<br>Hope it helps ....and haa don\'t by seeing its size???<br>As we know...Ionisation enthalpy is defined as the amount of energy required to remove an electron from an isolated gaseous atom............And now the answer of ur question is as we go down the group , the size of atom increases ,therefore...distance b/w electron(outermost shell) and nucleus is get increased ...therefore , force of attra . Is less blw nucleus and electron...therefore, less ionization enthalpy is required as we go down the group....<br>Just because the number of shells increase down a group. Due to which energy needed to ionise an electron becomes easy as Z effective decreases.

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