Lather Meyer drew a graph showing the relation between atomic `"_____"` and atomic `"____"` .

Explanation

To answer the question regarding Lothar Meyer’s graph, we need to identify the two parameters that he plotted against each other.

### Step-by-Step Solution:

1. **Identify the Parameters**: Lothar Meyer drew a graph to show the relationship between two specific properties of elements. These properties are:
- Atomic Volume
- Atomic Mass

2. **Understanding Atomic Volume**: Atomic volume is defined as the volume occupied by one mole of an element. It can be calculated using the formula:
\[ \text{Atomic Volume} = \frac{\text{Atomic Mass}}{\text{Density}} \]
This means that atomic volume is dependent on both the atomic mass of the element and its density.

3. **Graph Characteristics**: In the graph, atomic mass is typically plotted on the x-axis, while atomic volume is plotted on the y-axis. This allows for the visualization of how atomic volume changes with increasing atomic mass.

4. **Observations from the Graph**:
- The peaks of the graph correspond to alkali metals (like lithium, sodium, potassium).
- The descending positions are occupied by alkaline earth metals.
- The minima of the graph correspond to transition elements.
- The ascending positions are occupied by halogens.

5. **Final Answer**: Therefore, the blanks in the question can be filled as follows:
- Lothar Meyer drew a graph showing the relation between atomic **volume** and atomic **mass**.