Which observation about ionization energies provides evidence for the quantization of electron energies in atoms?

• A. Ionization energies are identical for all elements in the same period.
• B. Ionization energies increase smoothly as more electrons are removed.
• C. All electrons in an atom require the same amount of energy to be removed.
• D. Successive ionization energies show large jumps when removing electrons from a new energy level.

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.
2. Recognize that electrons in atoms occupy discrete energy levels or shells, which is a key idea in quantum theory.
3. Note that if electron energies were not quantized, ionization energies would change smoothly and continuously as electrons are removed.
4. Observe that successive ionization energies often show large jumps when electrons are removed from a new, closer energy level to the nucleus, indicating distinct energy levels.
5. Conclude that these large jumps in ionization energy provide evidence that electrons exist in quantized energy levels rather than a continuous range of energies.