Respuesta :
Explanation:
A. Calcium (Ca) and Radium (Ra): Radium is more electronegative than calcium. Both are alkaline earth metals in Group 2, but radium, located lower in the group, has more electron shells and a greater effective nuclear charge. This allows radium to more easily attract and retain shared electrons compared to calcium.
B. Lithium (Li) and Oxygen (O): Oxygen is more electronegative than lithium. Despite lithium being in Group 1 (alkali metals) and oxygen in Group 16 (chalcogens), the difference in their group numbers is significant. Oxygen's position on the right side of the periodic table results in higher electronegativity due to a greater effective nuclear charge and smaller atomic size, making it more efficient at attracting and holding electrons.
In both cases, the trend holds: the element lower in the group or further to the right on the periodic table is more electronegative. This aligns with the general trends of electronegativity: increasing from left to right across a period and increasing from bottom to top in a group.
I hope this clarifies the concept!
