Question 9

Potassium is most likely to become a cation.

Potassium, with an atomic number of 19, has one electron in its outermost shell, making it more likely to lose that electron and form a cation with a positive charge.

A) Potassium, atomic number 19

Potassium is in Group 1 of the periodic table, where elements tend to lose one electron to achieve a stable electron configuration, similar to the noble gases. This characteristic makes potassium highly reactive and very likely to form a cation (K⁺) by losing its single valence electron.

B) Oxygen, atomic number 8

Oxygen has six electrons in its outer shell and typically gains two electrons to achieve a full octet, resulting in the formation of an anion (O²⁻). Therefore, oxygen is less likely to become a cation, as it prefers to gain rather than lose electrons.

C) Fluorine, atomic number 9

Fluorine has seven electrons in its outer shell and tends to gain one electron to complete its octet, forming a negatively charged ion (F⁻). Similar to oxygen, fluorine's behavior indicates that it is not likely to become a cation.

D) Helium, atomic number 2

Helium has a full outer shell of two electrons and is classified as a noble gas. Noble gases do not readily lose or gain electrons, making helium highly stable and unlikely to become a cation or anion.

Conclusion

Potassium stands out as the most likely candidate to form a cation due to its position in Group 1 of the periodic table, where elements typically lose one electron. In contrast, oxygen and fluorine are more inclined to gain electrons and form anions, while helium remains inert and does not participate in ion formation. Thus, potassium's tendency to lose an electron solidifies its role as the most probable atom to become a cation.