When ionization energy is supplied to an atom, which of the following can be removed from the atom?

• A. A nucleus
• B. A proton
• C. A neutron
• D. An electron

Answer: (D)

Verified step by step guidance

1. Understand that ionization energy is the energy required to remove an electron from an atom or ion in its gaseous state.
2. Recall that the nucleus of an atom contains protons and neutrons, which are held together by the strong nuclear force and are not affected by typical ionization energies.
3. Recognize that protons and neutrons are located in the nucleus and cannot be removed by ionization energy; removing them requires nuclear reactions, not chemical ionization.
4. Identify that electrons are located in the electron cloud surrounding the nucleus and are held by electromagnetic forces, which can be overcome by supplying ionization energy.
5. Conclude that when ionization energy is supplied, it removes an electron from the atom, resulting in a positively charged ion.