Answer:
Step-by-step explanation:
K: 2, 8, 8, 1 but 19p+
K+: 2, 8, 8 but 19p+
Ca: 2, 8, 8, 2 but 20p+
Ca2+, 2, 8, 8 but 20p+
K and Ca are larger than their corresponding ions because of one more energy level, so Li is the smallest.
K and Ca have the same no. of electron shells but K has less p+ than Ca. so the attraction between electron and p+ in K is less than that in Ca. Therefore, K is larger than Ca.