Answer:

The atomic radius is the size of an atom. It measures an atom’s size. If an element is a metal, its radius is metallic, and if it is not a metal, its radius is covalent. The metallic radius is the inter-nuclear distance divided by two. In solid copper, the distance between two adjacent copper atoms is 256 pm.

Metallic radius of copper = {256}/{2}pm = 128pm

Covalent radius is the distance between two atoms connected by a single bond in a covalent atom. For example, the interatomic distance between two chlorine atoms is 198 pm.

Covalent radius of copper = 198/{2}pm = 99pm

Ionic radius is the size of an ion (cation or anion). ionic radius is calculated by measuring the distance between cation and anion. Because cations are formed by removing an electron from an atom’s outermost orbit, they have fewer electrons than the parent atom, resulting in a higher effective nuclear charge.

So a cation is smaller than the parent atom. For example, the ionic radius of sodium ion is 95 pm, while the atomic radius is 186 pm. An ion is larger than its parent atom. Because an anion has the same nuclear charge as the parent atom, but more electrons, it has less effective nuclear charge. For example, F-F (fluorine ion) has an ionic radius of 136 pm and an atomic radius of 64 pm.