Which atom or ion is the largest? a. k b. k+ c. ca d. ca2+ e. li

Option (C) is the correct answer.

Explanation:

When a neutral atom or element gain one or more number of electrons then it acquires a negative charge. Whereas when a neutral atom or element loses one or more number of electrons then it acquires a positive charge.

For example, potassium (K) when loses its one valence electron then it becomes .

So, more is the positive charge on an atom more will the electrons lost by it. Hence, atomic size decreases due to loss of electrons. Whereas more is the negative charge on an atom more will be the electrons gained by it.

Hence, more is the addition of electrons in an atom more will be its size.

Out of the given options Ca is a group 2 element and size increases on moving down the group. So, Ca is larger in size as compared to Li.

Thus, we can conclude that Ca atom or ion is the largest.