Question

ionisation enthalpy of an elements in a group: increase
decrease
constant
invariable charge​

Answer 1

Answer:

Ionisation energy decreases as we go down a group. As we go down a group, the atomic radii of the elements increase, the number of electrons shells also increases, thus, the nuclear attraction over a valence electron decreases and ionisation energy also decreases.

Ionisation energy generally increases across a period from left to right. As we move across a period from left to right, the atomic radii decreases, and the nuclear attraction over a valence electron increases. Thus, ionisation energy increases.