Question

What is the correct order of size (from smallest to largest) of K, K+, Ca and Ca2+?

Answer 1

your answer- Ca2+,Ca,K,K+

Answer 2

The correct order of size is-

$K>Ca>K^+>Ca^{+2}$

• The size of a species depends on its charge density and number of electrons.
• As the number of electrons increases the size of a species decreases due to the strong attraction of electrons towards the nucleus. Thus K has a larger size than Ca.
• Again if the charge on a species increases its size decreases thus Ca possess a higher charge and have a low size.
• Thus the correct order of size is-
• $K>Ca>K^+>Ca^{+2}$