When drops of mercury are placed on a clean surface of glass,they merge and become a single drop. Explain.

(N/A) The adhesive force between mercury molecules and glass molecules is weak,while the cohesive force between the molecules of mercury is very strong.
Because the cohesive force is much greater than the adhesive force,the mercury atoms prefer to stay together rather than spread out on the glass surface.
As a result,the mercury drops do not wet the glass surface and tend to merge together to minimize their surface area,forming a single large drop.