Ionization energy is the amount of energy required to remove the

A outermost electron
B innermost electron
C outermost proton
D innermost proton
Is it A or B?

It's the outermost electron. You want the one that is the farthest from the nucleus.

The correct answer is option A, the outermost electron. Ionization energy is the energy required to remove an electron from an atom or ion in its gaseous state.

To determine the correct answer, you could start by understanding the terms and concepts involved. Ionization energy refers to the energy needed to remove an electron from an atom or ion. Atoms consist of a nucleus composed of protons and neutrons, surrounded by electrons in energy levels or shells. Electrons are negatively charged particles, while protons are positively charged particles found in the nucleus.

By considering this information, we can deduce that the ionization energy refers to the energy required to remove an electron. As the outermost electron is typically the most loosely held electron and is furthest from the nucleus, it requires the least amount of energy to be removed compared to electrons in inner energy levels. Therefore, option A - the outermost electron - is the correct answer.