Final answer:
Ionization energy is the term used to describe the amount of energy required to remove an electron from an atom.
Step-by-step explanation:
The energy required to remove an electron from an atom is called ionization energy. Ionization energy measures the strength of the attraction between the nucleus and the electron. It is the minimum amount of energy needed to remove an electron from an atom in its ground state. For example, the first ionization energy of hydrogen is 1312.0 kilojoules per mole (kJ/mol).