1. The problem is to understand the trend of melting points in Group 1 elements of the periodic table. 2. Group 1 elements include Lithium, Sodium, Potassium, Rubidium, Caesium, and Francium. 3. The graph shows melting points decreasing from Lithium to Francium. 4. This trend occurs because as you move down Group 1, atomic size increases, causing weaker metallic bonds and thus lower melting points. 5. Lithium has the highest melting point near 180°C, and Francium has the lowest near 23°C. 6. Therefore, the melting points decrease down the group, confirming the trend shown in the graph.