Question

Arrange the following in order of increasing size:

F^- F K K⁺

Select one:

fluorine < fluoride < potassium ion < potassium

fluoride < fluorine < potassium < potassium ion

potassium ion , fluorine < potassium < fluoride

fluoride < fluorine < potassium ion < potassium

Answer 1

K and K+ will be larger than F and F- because of extra shell present in K and K+.

Between K and K+, K is larger. This is because K+ has one less electron and hence there is less electron electron repulsion as compared to K. So, K+ would be smaller.

F- is larger than F. This is because F has one extra electron and hence greater electron-electron repulsion.

So, order is:

F < F- < K+ < K

Answer: fluorine < fluoride < potassium ion < potassium