Final answer:
Rubidium (Rb) is the element that would most likely lose electrons to form positive ions when bonding with other elements.
Step-by-step explanation:
The element that would most likely lose electrons to form positive ions when bonding with other elements is rubidium (Rb).
Rubidium is an alkali metal found in Group 1 of the periodic table. It has only one valence electron in its outermost energy level, which makes it highly reactive. When rubidium forms ions, it loses this valence electron to achieve a stable electron configuration, resulting in the formation of a positively charged ion.
For example, rubidium can lose its valence electron to form the ion Rb+. By losing an electron, rubidium achieves the same electron configuration as the noble gas just before it in the periodic table, which is typically more stable.
Learn more about Formation of positive ions in chemical bonding