Why does atomic radius change as it does

Most questions answered within 4 hours. Choose an expert and meet online. No packages or subscriptions, pay only for the time you need. Why does atomic number increase as atomic radius decreases? This is for chemistry class. Add comment. Ahh a wonderful question. AS you across the periodic table the atomic number increases, but the atomic radius decreases.

Ask a question for free Get a free answer to a quick problem. The radius of each atom in an ionic bond will be different than that in a covalent bond. This is an important concept. The reason for the variability in radius is due to the fact that the atoms in an ionic bond are of greatly different size.

One of the atoms is a cation, which is smaller in size, and the other atom is an anion which is a lot larger in size. So in order to account for this difference, one most get the total distance between the two nuclei and divide the distance according to atomic size.

The bigger the atomic size, the larger radius it will have. If we were able to determine the atomic radius of an atom from experimentation, say Se, which had an atomic radius of pm, then we could determine the atomic radius of any other atom bonded to Se by subtracting the size of the atomic radius of Se from the total distance between the two nuclei. So, if we had the compound CaSe, which had a total distance of pm between the nucleus of the Ca atom and Se atom, then the atomic radius of the Ca atom will be pm total distance - pm distance of Se , or pm.

This process can be applied to other examples of ionic radius. Cations have smaller ionic radii than their neutral atoms. In contrast, anions have bigger ionic radii than their corresponding neutral atoms.

Figure 3 below depicts this process. An anion , on the other hand, will be bigger in size than that of the atom it was made from because of a gain of an electron. This can be seen in the Figure 4 below. The gain of an electron adds more electrons to the outermost shell which increases the radius because there are now more electrons further away from the nucleus and there are more electrons to pull towards the nucleus so the pull becomes slightly weaker than of the neutral atom and causes an increase in atomic radius.

The metallic radius is the radius of an atom joined by metallic bond. The metallic radius is half of the total distance between the nuclei of two adjacent atoms in a metallic cluster.

Since a metal will be a group of atoms of the same element, the distance of each atom will be the same Figure 5. The electron configuration of the transition metals explains this phenomenon. This is why Ga is the same size as its preceding atom and why Sb is slightly bigger than Sn. Why is the number of protons and electrons equal in an atom? Question 2b Question a Question c0a6c.

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