When a hydrogen atom absorbs electromagnetic radiation (light), which of the following occurs?

• A. An electron in the atom moves from a lower energy level to a higher energy level.
• B. The atom emits a photon and its electron drops to a lower energy level.
• C. The nucleus of the atom splits into two smaller nuclei.
• D. The atom loses an electron and becomes a negatively charged ion.

Answer: (A)

Verified step by step guidance

1. Understand the structure of a hydrogen atom: it consists of one proton in the nucleus and one electron orbiting in discrete energy levels.
2. Recall that when an atom absorbs electromagnetic radiation (light), energy is transferred to the electron, allowing it to move from a lower energy level (ground state) to a higher energy level (excited state).
3. Recognize that emission of a photon occurs when an electron drops from a higher energy level to a lower energy level, releasing energy, which is the opposite process of absorption.
4. Note that the nucleus of a hydrogen atom does not split under normal absorption of light; nuclear reactions require much higher energies and different conditions.
5. Understand that losing an electron results in a positively charged ion (cation), not a negatively charged ion, and this process is called ionization, which is different from simple absorption of light causing an electron to move between energy levels.