What do you mean by covalent radius?
where 198 pm = Internuclear distance between two chlorine atoms (Cl—Cl) in a molecule of Cl2.
In case of heteronuclear molecules (containing different atoms) such as HCl, the covalent radius may be defined as: “The difference of the distance between the nuclei of two bonded atoms and covalent radius of one of the atoms in a heteronuclear molecule.”
Covalent radius = [Internuclear distance of two bonded atoms] -[Covalent radius of one of the two atoms in heteronuclear molecules]
For example,
Covalent radius of H-atom (in HCl)
= Internuclear distance of HCl - covalent radius of Cl atom
= 136 pm - 99 pm = 37 pm.
Why do the noble gas elements have exceptionally high atomic radii?
Or
In a period, generally the size of the atom decreases with rise in atomic number, but at the end of each period, atomic size of the noble gas increases abruptly. Why is it so?
