Question

Why is Na less reactive than K?

Answer 1

Na is less reactive than K

Both sodium and potassium belong to group I and need to lose only one electron to achieve a noble gas configuration. However, sodium is much smaller in size than potassium. Thus in sodium, the electrostatic attraction between the nucleus and outermost electron is more because of which it loses electrons less easily as compared to potassium. Potassium's outermost electron is farther away from the nucleus, as a result of which it is easier for potassium to lose its outer electron than it is for sodium.