Atomic radius of an atom can be measured as

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The atomic radius of an atom is not fixed, as atoms are not solid spheres like balls. Instead, it is measured based on the distance between the nuclei of two adjacent atoms and halving this distance. Therefore, Option D is correct: the atomic radius is determined by measuring the distance between two touching atoms and dividing it by two.

Concept Explanation:

Atoms are tiny particles that do not have clearly defined boundaries. Instead of having a fixed radius, the atomic radius is influenced by the type of bond between atoms and the physical environment. This measurement is not absolute and varies depending on the method used to define the radius.

There are different types of atomic radii based on the bonding or arrangement of atoms, such as:

1. Covalent Radius: Measured for atoms bonded by covalent bonds. It is the distance between the nuclei of two bonded atoms, divided by two.
2. Van der Waals Radius: Used for atoms in non-bonded situations. It refers to half the distance between the nuclei of two adjacent non-bonded atoms.
3. Metallic Radius: Applicable for atoms in a metallic lattice, measured as half the distance between nuclei in a metallic bond.
4. Ionic Radius: Defined for ions in ionic compounds, varying based on whether the atom gains or loses electrons (cation or anion).