Define (a) ionic radii and (b) covalent radii.

Ionic radii are

Ionic radii are

Ionic radii of

Ionic radii of :

Ionic radii vary in

Give an example each of an ionic hydride and a covalent hydride.

Define various types of atomic radii. Why is covalent radius smaller than metallic and van der Waals' radii ? How do atomic radii vary in a group and in a period.

In the following questions a statement of assertion (A) is followed by a statement of reason ( R) A : Atomic radii decreases in a period upto halogen . R : van der Waal radii of CI is larger than its covalent radii.

Write the trend of variation in atomic and ionic radii among the alkali metals.

The ionic radii of A^(+) and B^(-) are 1.7 Å and 1.8 Å respectively . Find the co-ordination number of A^(+)