Which is the least metallic, Lead, mercury, americium, or francium?

Answer: Lead will be the least metallic of all the elements given.

Explanation: Metallic character is defined as the tendency of the metals to loose electrons easily.

The metallic character increases down the group and decreases across a period because the size of the elemnt increases down the group and decreases across a period.

Lead belong to Group 14 and Period 6 of the periodic table.

Mercury belongs to Group 12 and Period 6 of the periodic table.

Americium belongs to Group 8 and Period 7 of the periodic table.

Francium belongs to Group 1 and Period 7 of the periodic table.

Order of metallic character:

Francium > Americium > Mercury > Lead

From the order above, the lead will have the least metallic character.