As lithium and magnesium have approximately same size do sodium and calcium have the same size? If not why?

Asked by Alekhya K | 9th Dec, 2013, 12:35: PM

Expert Answer:

Lithium and magnesium have approximately same size because there exist diagonal relationship between them.

The diagonal relationship does not exist between third and fourth periods such as between sodium and calcium. Thus, the atomic size of calcium 100 (Z=20) is larger than that of sodium (z=11).

This is because atomic size of elements in the same group increase down the group. Since, atomic number increases down the group, number of shells increases and atomic size increases. Thus, Atomic radius of sodium is 186 pm and that of calcium is 197 pm.

Answered by Hanisha Vyas | 9th Dec, 2013, 01:33: PM

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