What term describes the process by which radiant energy removes an orbital electron from an atom?

The correct term that describes the process by which radiant energy removes an orbital electron from an atom is ionization. This process occurs when an atom absorbs sufficient energy, often from electromagnetic radiation, leading to the ejection of one of its electrons. The atom then becomes positively charged as a result of losing a negatively charged electron, resulting in an ion. Understanding this concept is fundamental in radiation safety, as ionization can lead to changes in cellular structures and potentially cause biological effects, including damage to DNA.

Other terms mentioned, such as excitation, refer to a different process where energy absorbed by an atom causes an electron to move to a higher energy level without being completely removed from the atom. Radiation is a broader term that encompasses various forms of energy emission, including both ionizing and non-ionizing radiation, but it does not specifically define the removal of an electron. Fluorescence pertains to the emission of light by a substance that has absorbed light or other electromagnetic radiation, and it does not involve the removal of electrons in the context of ionization.