What increases ionic radius?
Ionic radii increases down a group. In a group, all the ions have the same charge as they have the same valency (that is, the same number of valence electrons on the highest energy level sub-orbital). Therefore, ionic radii increase down a group as more shells are added (per period).
How do you arrange ions in order of increasing atomic radius?
In such a series, size decreases as the nuclear charge (atomic number) of the ion increases. The atomic numbers of the ions are S (16), Cl (17), K (19), and Ca (20). Thus, the ions decrease in size in the order: S2- > Cl– > K+ > Ca2+.
What causes the increased atomic radius of an anion?
An anion has a larger radius than the neutral atom because it gains valence electrons. There are added electron/electron repulsions in the valence shell that expand the size of the electron cloud, which results in a larger radius for the anion.
When does the ionic radius of an element increase?
As with other types of atomic radii, ionic radii increase upon descending a group and decrease going across a period. Note that this only applies if the elements are the same type of ion, either cations or anions.
How are atoms and ions related in ionic radii?
Sizes of atoms and their ions Relative sizes of atoms and ions. The neutral atoms are colored gray, cations red, and anions blue. As with other types of atomic radii, ionic radii increase upon descending a group and decrease going across a period.
Why does atomic radius decrease as you move down periodic table?
On the periodic table, atomic radius generally decreases as you move from left to right across a period (due to increasing nuclear charge) and increases as you move down a group (due to the increasing number of electron shells). Similar trends are observed for ionic radius, although cations and anions need to be considered separately.
How is the atomic radius of an atom calculated?
Atomic radii reported in units of picometers (pm). Data taken from John Emsley, The Elements, 3rd edition. Oxford: Clarendon Press, 1998. The atomic radius is the distance from the nucleus of an atom to the outermost electrons.
