Ionization energy - 1 | Quantum Theory and Atomic Structure

1) How do we call the minimum energy required to remove the most loosely held electron?

2) For which of the following atom this energy will be the highest? I, Na, Cs, K, Cl

3) Is this process endothermic or exothermic?

1) first ionization energy

2) Cl

3) endothermic (requiring the absorption of heat)