Based on the trend of electronegativities values of the elements Be, Mg, Ca, and, Sr within their group (increasing from bottom to top), the atoms of the element Sr will have the least attraction for an electron.
We need to remember that electronegativity indicates the affinity or attraction of an element for an electron. Hence, the higher the electronegativity, the higher the attraction of that element for an electron.
The values of electronegativities of the given elements are the following:
Be = 1.57
Mg = 1.31
Ca = 1.0
Sr = 0.95
We can see that the increasing trend of electronegativities in this group is from the bottom to the top, having the Sr with the lowest electronegativity value and the Be with the highest.
This trend is related to atomic size, the larger the atomic size, the lower the electronegativity because the electron in the outermost shell will feel less attraction towards the nucleus of an atom. In a group of the periodic table, the size of an atom will increase from top to bottom.
Therefore, according to the said above, the atoms of the Sr will have the least attraction for an electron (it has the lower electronegativity value).
Find more about electronegativity here:
I hope it helps you!
