Which is the most electropositive element?
A.Na
B.Cu
C.Cs
D.Ca

Hint: The electropositivity of an element increases as we go down a group and it decreases as we go from left to right along a period in the periodic table. So the most electropositive element will be present at the left down corner in the periodic table.

Complete step by step answer:
- Electropositivity of an element can be defined as the ability of an elements to lose or donate electrons to other elements and form positively charged cations. The elements that show this electropositive nature are known as electropositive elements.
- The property of electropositivity is primarily exhibited by the metallic elements, i.e., mostly the group 1 and group 2 elements, also known as the alkali metals and the alkaline earth metals, in the periodic table.
- Electropositivity increases as we go down a group and it decreases as we go from left to right along a period. This is due to the fact that as we go down a group, the radius of the atom gets increased due to the adding of new shells.
- As a result, the tendency of an element to lose an element also increases down a group, and thus leads to an increase in the electropositivity of the elements.
Therefore, applying this logic to the given question, we can say that the most electropositive element among these is cesium. Hence, the correct option is option (c).

Note: Electropositivity of an element is inversely proportional to the electronegativity of an element. The greater the electropositivity of an element, the smallest will be its electronegativity. Hence, the most electropositive elements are the least electronegative elements.