Bond length is defined as the equilibrium distance between the nuclei of two bonded atoms in a molecule.
The Covalent Radius is measured approximately as the radius of an atom’s core which is in contact with the core of an adjacent atom in a bonded situation.
Van der Waals Radius
The van der Waals radius represents the overall size of atoms which included the valence shell in a non-bonded situation.
Bond Angle is defined as the angle between the orbitals containing bonding electron pairs around the central atom in a molecule/ion.
Bond Enthalpy is defined as the amount of energy required to break one mole of bonds of a particular type between two atoms in a gaseous state. For Polyatomic molecules, the term mean or average bond enthalpy is used.
Bond order is given by the number of bonds between the two atoms in a molecule. With the increase in bond order, bond enthalpy increases and bond length decreases.