Question

Why is the ionization energy for s electron more than d electron for the same n value

Answer 1

When u draw electronic configuration u will observe that s electron lies away from valence shell and d electrons are filled after filling s and p electrons.enegy level. Ns

Answer 2

it is because s electrons are located more closer to nucleus and hence have high nuclear pull and thus high energy is required to remove an electron from s orbital rather than d orbital for same N value