Which of the following elements has the least tendency to form an ion?
A)Ca
B)K
C)Kr
D)Se

Question

Quizplus · Accepted Answer

Kr (krypton) is a noble gas, which means it has a complete outer electron shell and is therefore unreactive. As a result, it has the least tendency to form an ion. The other three elements (Ca, K, and Se) are all metals that tend to lose electrons and form positively charged ions (called cations) to achieve a stable electron configuration.

Which of the Following Elements Has the Least Tendency to Form