The difference between the energy maximum along a reaction path and the energy of the reactant is called activation energy.

Answer

To solve the question regarding activation energy, we will follow these steps:

### Step 1: Understand the Concepts
Activation energy (Ea) is defined as the minimum amount of energy required for a chemical reaction to occur. It is the energy barrier that must be overcome for reactants to be transformed into products.

### Step 2: Draw the Potential Energy Diagram
To visualize activation energy, we can draw a potential energy diagram.

- **Y-axis**: Represents the energy of the system.
- **X-axis**: Represents the progress of the reaction.

### Step 3: Identify Reactants and Products
On the diagram:
- Mark the energy level of the reactants (R).
- Mark the energy level of the products (P).

### Step 4: Identify the Activated Complex
- The peak of the curve in the diagram represents the activated complex (also known as the transition state), which is the state of highest energy during the reaction.

### Step 5: Calculate Activation Energy
- The activation energy (Ea) is the difference between the energy of the activated complex and the energy of the reactants. Mathematically, it can be expressed as:

\[ E_a = E_{\text{activated complex}} - E_{\text{reactants}} \]

### Step 6: Conclusion
The statement in the question is true: the difference between the energy maximum (the energy of the activated complex) and the energy of the reactants is indeed called activation energy.