Question

The most electropositive element is-
A. Cs
B. C
C. Cl
D. K

Answer 1

Hint: We can identify an electropositive element if its electrode potential is more positive than that of the standard hydrogen electrode. In electrochemistry, it (standard hydrogen electrode) is defined to have a potential of zero volts.

Complete step by step answer:
An electropositive element is an element with atoms that have a tendency to lose electrons and form positive ions. It is an element with very low electronegativity.
Alkali metals are the most electropositive elements. The element of group 1 has the highest metallic character and thus is the most electropositive element. Also, similar to the metallic character, the electropositive character increases down the group. Caesium (Cs) metal is at the last in the group of alkali metals, thus it is the most electropositive element.
In Cs, there are many shells and no. of electrons are more. But in the outermost shell there is only one electron. The attraction of the nucleus of caesium is very less to the outermost electron, so it is likely to lose its electron to obtain the most stable state. Thus, it is the most electropositive element.

Thus, the correct answer is option A. i.e., 4.

Additional Information:
Caesium is the most electropositive stable element. Francium is more electropositive than Caesium but not stable as it is highly radioactive.

Note: Electropositive elements often form ionic salts with electronegative elements. Electro positivity is the measure of the ability of elements to donate electrons to form positive ions. Next to astatine, francium is the second rarest element in the Earth’s crust.