Question

Which element has the most metallic character?

Answer 1

Hint: The modern periodic table contains all the chemical elements arranged in groups (vertical columns) and periods (horizontal rows) according to their atomic numbers. This arrangement leads to a series of trends in chemical properties of the elements making it easier to compare.

Complete answer:
Elements placed in the modern periodic table show periodicity in the occurrence of specific properties.
Majority of elements in the periodic table are metals (soft or hard) and occupy the left side of the table. Towards the right, we find metalloids followed by non-metals.
Metals can be compared to one another based on their ability to show reactions. Some metals tend to show vigorous reactions with air, water and acids. Some metals show endothermic reactions that are kinetically very slow. Such observations are based on the reactivity of metals which is defined by their metallic character.
Metallic character is the ability of a metal to readily react i.e. readily lose electrons. The metal must be highly electropositive in nature, should have a large size, low ionization enthalpy and less effective nuclear charge. All these factors combined together are responsible for making a metal highly reactive.
The ionization enthalpy decreases on going down a group and increases left to right in a period, the size increases down the group and decreases across a period. Thus the overall metallic character is high on the extreme left bottom of the periodic table. The first group of alkali metals are the most metallic elements with francium having the highest metallic character as it lies at the bottom most position.
Hence, Francium $$Fr$$ is the most metallic element followed by Caesium $$Cs$$ .

Note:
The trends in the decrease of effective nuclear charge follows the same trend as that of ionization enthalpy rather ionization enthalpy’s trend is a consequence of decreasing effective nuclear charge. Electropositivity is dependent on both size and ionization enthalpy.