Question

The correct order of electropositive character of given elements is:
A.$Li > Na > K > Rb > Cs$
B.$Li < Na < K < Rb < Cs$
C.$Li > Na < K < Rb < Cs$
D.$Li > Na > K < Rb < Cs$

Answer 1

Electropositivity can be defined as the tendency of an atom to donate electrons and form positively charged cations. This property is primarily exhibited by metallic elements, especially the alkali metals and the alkaline earth metals. It is important to notice that electropositivity is the opposite of electronegativity, which may be a measure of the tendency of an atom to release electrons and form charged anions.

Complete step by step answer:
Factors affecting electropositivity of elements:
The electropositivity of a component depends on several factors like the metallic character of the element, the space between the nucleus and therefore the valence shell, the effective nuclear charge working on the valence electrons, and therefore the ionization energy of the element.
Periodicity trend of electropositivity in periodic table:
The periodic trends within the electropositivity exhibited by elements are always opposite to the periodic trends within the electronegativities of elements. Since electronegativity increases across a period, electropositivity decreases across periods. Similarly, since electronegativity decreases down a bunch, electropositivity increases while traversing down a bunch. Therefore, the weather at the top-right of the table is the smallest amount electropositive and therefore the elements at the bottom-left of the table are the most electropositive.
So from above theory we can conclude that electropositivity increases down the group;
Thus; option B is correct.

Note:
Highly electropositive elements have very low electronegativities and highly electronegative elements have very low electropositivity (electronegative elements typically don't have the tendency to lose electrons to make cations and electropositive elements generally don't to realize electrons to make anions).