Which of these groups of elements show the least electronegativity?
inner-transition elements
a. halogens
b. alkali metals
c. transition elements
d. alkaline earth metals

The correct answer is Option B.

Explanation:

Electronegativity is defined as the property of as element to attract the shared pair of electron towards itself. The value of electronegativity is high for non-metals because they can easily gain electrons as compared to the metals.

This value decreases as we move down the group and increases as we move across a period.

Halogens are the elements which belong to Group 17. They easily gain electrons in order to attain stability. Thus, these elements have high electronegativity values.

Alkali metals are the elements which belong to Group 1. They easily loose electrons in order to attain stability and thus have low electronegativity.

Transition elements are the elements which belong from Group 3 to Group 12. They easily loose electrons in order to attain stability and thus have low electronegativity.

Alkaline earth metals are the elements which belong to Group 2. They easily loose electrons in order to attain stability and thus have low electronegativity.

From the above information, the elements which belong o Group 1 have the lowest electronegativity values.

Hence, the correct answer is Option B.