What is ionization energy?

What is ionization energy?

• A. The energy produced when an atom accepts an electron.
• B. The energy required to remove an electron from an atom.
• C. The energy required to break a chemical bond.
• D. The energy change in a nuclear reaction.

Answer: (B)

Ionization energy is the energy required to remove an electron from an atom in its gaseous, ground state. Because electrons are held by the positive nucleus, you must supply energy to overcome that attraction, so the process is endothermic. The amount of energy depends on how strongly the nucleus attracts the electrons and how much shielding there is; generally it gets larger when removing successive electrons and across a period. This concept describes removing an electron, not gaining one (that would be electron affinity), not breaking a chemical bond (bond dissociation energy), and not any energy change from a nuclear reaction.

Ionization energy is the energy required to remove an electron from an atom in its gaseous, ground state. Because electrons are held by the positive nucleus, you must supply energy to overcome that attraction, so the process is endothermic. The amount of energy depends on how strongly the nucleus attracts the electrons and how much shielding there is; generally it gets larger when removing successive electrons and across a period. This concept describes removing an electron, not gaining one (that would be electron affinity), not breaking a chemical bond (bond dissociation energy), and not any energy change from a nuclear reaction.