Atomic Radius Definition

Theoretically, an electron, at one time, may be very close to the nucleus while at other time it may be far away from the nucleus. So, on certain facts, it is difficult to explain the exact atomic radius definition. Let’s explain it more clearly.

Atomic Radius Definition

Definition of Atomic radius – It is defined as the distance between the nucleus and outermost orbit. However, there is no certainty about the exact position of electrons at any time.  Also, It is not possible to measure the exact value of the atomic radius of an atom of the element because an atom is very much smaller in size.

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Why not possible to exact determination?
A. It is not possible to isolate a single atom.
B. It is not possible to measure the exact distance of the atom does not have a well-defined shape or boundary and the probability of electron is level zero even at a large distance from the nucleus.
C. It is likely to change due to environmental effect and many more reasons.Atomic Radius [ Define, Periodic Table Trend, chart] how to find atomic radius, Largest atomic radius

However, we can express the different forms of atom depending upon the nature of the bonding of atomsIn spite of the above limitations, There are three operational concepts:

The are three types of atomic radius.Atomic Radius Definition

  •  Covalent radius: If bonding present in between atoms in a molecule is covalent, the radius is called covalent radius. It is half of the distance between the nucleus of two like atoms bonded together by a single bond or by a covalent bond.
  • Metallic radius: It is defined as one half of the inter nuclear distance between the nucleus of two adjacent atoms in the metallic lattice. The metallic radius of an element is greater than the covalent radius. 
  • Van der Waal’s radius: It is one half of the distance between the nucleus of two adjacent atoms belonging to two neighboring molecules of an element in the solid state.


This is the basic atomic radius definition.