What is covalent radius ?

Al and Ga have nearly the same covalent radius, incorrect reason is

If the atomic radius of non-metal bromine is 1.14 Å, its covalent radius is

Identify the correct order in which the covalent radius of the following elements increases. Q I. TI II.Ca III. Sc

What is crystal radius (or) metallic radius ?

Match it . {:("a) Cu","(i) metallic radius "),("b) Cl","(ii) covalent radius "):}