Question

Explain what you understand by covalent radius, Van Der Waals radius, ionic radius, and atomic radius.

Answer 1

Step 1: Covalent Radius

1. A covalent radius is defined as the radius of an atom when it is part of one covalent bond.
2. Hence, if two atoms are bonded to each other with a covalent bond, the sum of their two respective covalent radii will give the equivalent bond length.

Step 2: Van Der Waals Radius

1. Van der Waals forces are relatively weak electric forces in which neutral molecules are attracted to one another.
2. Van Der Waals radius is the radius of an atom that is not a part of any covalent or ionic bond.

Step 3: Ionic Radius

1. Since an ion is formed due to the interaction of electrons present in the outermost shell, hence an ionic radius is said to be the distance between the center of an atom inside the nucleus and the outermost atomic shell.
2. When a cation is formed due to the loosing of an electron, the ionic radius decreases.
3. When an anion is formed due to the gaining of an electron, the ionic radius increases.

Step 4: Atomic Radius

1. Atomic radius is the distance between the center of an atom inside the nuclei and its outermost orbital.
2. Using the value of atomic radius we can determine the size of an atom.