Question

Second ionisation potential ($I{P}_2$) of calcium is __________ $I{P}_2$ of potassium.

• A. less than
• B. more than
• C. equal to
• D. none of these

Answer 1

The correct option is B more than

Coming to comparison between potassium and calcium, they are placed across a period, with potassium appearing before calcium. As we know that the size of the atom decreases across a period and so the ionisation potential increases across a period, it will be easier for potassium to lose electron than calcium.

So this is why potassium can easily lose electrons when compared to sodium, calcium, magnesium.

Second ionisation potential (${IP}_2$) of calcium is more than ${IP}_2$ of potassium.