Consider the Mg2+, Cl-, K+, and Se2- ions. The four spheres below represent these four ions, scaled according to ionic size. A) Match each ion to its appropriate sphere. B) In terms of size, between which of the spheres would yo find the (i) Ca2+ and (ii) S2- ions?

The size of the spheres, going from smallest to largest, would be: , , , , , .

We can arrive at this answer because:

This is because when donating electrons, the cations get the largest number of protons. This makes the cation nucleus attract the electronic layers, decreasing their extension. In anion, the opposite happens and the increase of electrons increases the extension of the electronic layers.

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A is  Mg^2+

B is K^+

C is Se^2-

D is Cl^-

Ca^2+ lies between  Mg^2+ and K^+

S^2-  lies between K^+ and Se^2-

Explanation:

I have attached an image of the four spheres.

Remember that, cations are smaller in size than the corresponding atom atom because the formation of a cation often involves the removal of an entire shell. Anions are larger in size than the corresponding atom because an electron is added thereby expanding the electron cloud and size of the anion.

From left to right let us designate the spheres as ABCD.

A is  Mg^2+

B is K^+

C is Se^2-

D is Cl^-

Ca^2+ lies between  Mg^2+ and K^+

S^2-  lies between K^+ and Se^2-