Answer:
Strontium (St)
Explanation:
The atom that will have a larger radius than zinc is strontium, Sr.
Atomic radius is defined as the half of the inter-nuclear distance between two covalently bonded atoms of non-metallic elements or half of the distance between two nuclei in the solid state of metals.
Considering the definition of atomic radius, the atom that will have a larger radius than zinc is strontium, Sr.
The atomic radius represents the distance between the nucleus and the valence shell, which is the outermost shell. By means of the atomic radius it is possible to determine the size of the atom.
But the size of the atom or atomic radius is not an easy parameter to determine, since the electrons are not located in defined orbits, at fixed distances from the nucleus, but rather move chaotically in areas of space where the probability of finding the electron is greater than 90%.
Therefore, the atomic radius is considered as half the distance that separates two neighboring nuclei.
By increasing the atomic number of the elements in a group, that is, by going down in a group, the number of occupied levels is increased. Consequently, the atomic radius increases.
On the other hand, the atomic radius decreases as you advance through a period. This is due to the fact that when advancing in a period, while the number of electron shells remains the same, the positive charge of the nucleus increases due to the increase in the atomic number, that is, the number of protons, which have a positive charge. This causes the electrons to move closer to the nucleus, thus decreasing the radius.
In summary, in the groups, the atomic radius increases with the atomic number, that is to say downwards, while in the periods it decreases with increasing Z, towards the right.
Since strontium satisfies the criteria explained previously, it has the largest atomic radius.
Finally, the atom that will have a larger radius than zinc is strontium, Sr.
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