Atomic Radius:

(1)     The radius of an atom may be taken as the distance between atomic nucleus and the outermost shell of electrons of the atom.

(2)     According to the Heisenberg’s uncertainty principle the position of a moving electron cannot be accurately determined. So the distance between the nucleus and the outermost electron is uncertain.

(3)     Atomic radius can be determined indirectly from inter nuclear distance between the two atoms in a gaseous diatomic molecule. This internuclear distance between the two atoms is called bond length.

(4)     The internuclear distance between the two atoms can be measured by X– ray diffraction or spectroscopic studies and also nuclear magnetic resonance (NMR) spectrum.

(5)     Atomic radius depends on the type of chemical bond between atoms in a molecule. These are:

(i)   Covalent radius

(ii) Metallic radius or crystal radius

(iii) Vander Waal’s radius

(iv) Ionic radius or Collision radius

(6) Periodicity in Atomic Radius and Ionic Radius: 

Related Questions:

(1) What are the Amphoteric metals ? gives Examples.

(2) Name of total metalloids present in periodic table ?

(3) Total numbers of elements which are liquid at normal temperature is ?

(4) What is Mendeleev's periodic table ? give important features and draw back of Mendeleev's table.

(5) What is atomic density ? give the periodicity of atomic density in periods and groups.

(6) What is atomic volume ? and what is periodicity of atomic volume in groups and periods ?

(7) Why there are 2, 8 and 8 elements in first, second and third periodic of periods table respectively ? Explain.

(8) In alkali metal group which is the strongest reducing agent in aqueous solution and why?

(9) The electron affinity of sulphur is greater than oxygen. Why?

(10) The first ionization energy of carbon atom is greater than that of boron atom, whereas reverse is true for the second ionization energy. Explain.

(11) The electronegativities of B, Al, Ga are 2.0, 1.5, 1.6 respectively. The trend is not regular. Explain.

(12) Li2CO3 decomposes on heating but other alkali metal carbonates don’t. Explain.

(13) Of all noble metals, gold has got a relatively high electron affinity. Explain.

(14) What are the increasing order of ioni radii of first group elements in water ?

(15) What are the increasing order of molar conductivity of first group elements in water ?