# How do you know which ion has the largest radius?

## How do you know which ion has the largest radius?

The ionic radii of cations follow the same trends as atomic radii. They increase from top to bottom and from right to left in the Periodic Table. Thus, the ion with the largest radius is closest to the lower left corner of the Periodic Table, and that is the K+ ion.

How do you find the radius size?

The radius of an atom can only be found by measuring the distance between the nuclei of two touching atoms, and then halving that distance. As you can see from the diagrams, the same atom could be found to have a different radius depending on what was around it. The left hand diagram shows bonded atoms.

How do you determine the size of an ion?

You cannot predict ion size as a function of charge, but you can make statements about some general trends. In general, ionic radius decreases with increasing positive charge. As the charge on the ion becomes more positive, there are fewer electrons. The ion has a smaller radius.

### What is the ionic radius of Mg2+?

0.65 A
As the ionic radii of Mg2+ (0.65 A), Cu2+ (0.73 A) and Ni2+ (0.72 A) are appreciably smaller than Ca2+ (0.99 A), it appears that the Mn2+ binding site is more accessible to Mg2+, Cu2+, and Ni2+ as compared to Ca2+, the ionic radius of Mn2+ being 0.80 A.

How is the radius of an ion determined?

Identify the general trends of the ionic radius size for the periodic table. The ionic radius is the distance between the nucleus and the electron in the outermost shell of an ion.

Can you predict the size of an ion?

You cannot predict ion size as a function of charge, but you can make statements about some general trends. In general, ionic radius decreases with increasing positive charge. As the charge on the ion becomes more positive, there are fewer electrons.

## Is the ionic radius of an anion sharp?

Although neither atoms nor ions have sharp boundaries, it is useful to treat them as if they are hard spheres with radii. In this way, the sum of ionic radii of a cation and an anion can give us the distance between the ions in a crystal lattice.

How to calculate the ionic radius of RB +?

That is, the distance between two neighboring iodides in the crystal is assumed to be twice the radius of the iodide ion, which was deduced to be 214 pm. This value can be used to determine other radii. For example, the inter-ionic distance in RbI is 356 pm, giving 142 pm for the ionic radius of Rb+.