The minimum amount of energy required for a reaction to take place is

Correct answer: Activation energy

Explanation: The activation energy is the minimum energy that reacting particles must possess to collide effectively and form the activated complex, leading to products. A catalyst speeds up a reaction by lowering this activation energy but does not change the overall energy change of the reaction.

• Lattice energy — Energy change when gaseous ions form an ionic solid; not the threshold for a reaction.
• Ionization energy — Energy required to remove an electron from an atom or ion in the gaseous state.
• Activation energy — Correct. The minimum energy needed for a reaction to proceed.
• Kinetic energy — Energy of motion; particles need sufficient kinetic energy, but the defined threshold is the activation energy.