dat destroyer gen chem atomic radius

HELP, This was a question from the DAT Destroyer Gen. Chem. pg.115 Question: Rank by size : Al, K, Br, I Answer: K > Al > I > Br I thought the more electrons it has, the bigger the atom Al = 13e K = 19e Br = 35 e I = 53e So according to my logic, shouldn't the answer be I > Br > K > Al