Define ionisation energy. What is its value for Hydrogen atom?

Define Ionisation potential.

Define activation energy. What is Arrhenius equation?

The ionisation energy of hydrogen is:

The first ionisation energy is smallest for the atom with electronic configuration :

How does ionisation energy vary in a group ?

If the ionisation potential for hydrogen atom is 13.6 eV, then the wavelength of light required for the ionisation of hydrogen atom would be: