[en] There is currently tremendous progress being seen in all areas of chemistry and physics provoking many classical ideas of chemical bonding to be modified or even revised. It is therefore highly desirable to revisit basic quantities that are used in treating intra- and intermolecular interactions. In the present work, the following parameters or concepts are critically surveyed and/or updated: the ionic radius both in the crystal and in aqueous solution, the (static electric dipole) polarizability, the effective nuclear charge, lattice enthalpies, and the thermodynamic characteristics (enthalpy, free energy and entropy) of the dissolution of ionic salts in water. Restriction is to noble gas ions and, in addition, symmetrical polyatomic anions. The polarizability of molecular liquids has also been determined. Some of the results may be summarized as follows: 1. The concept of the 'general purpose' Bragg-Slater (BS) radii is refined by assowing for a change in the cation coordination number. In contrast, the anion radii is identified with the covalent radius taken as invariant. These modified BS radii appear to be physically more reasonable than traditional ionic radii, since by their use an intimidating array of radii (covalent, tetrahedral, ionic, metallic) can be brought under the umbrella of one treatment. 2. A simple equation is presented for calculating the enthalpy of dissolution of simple salts in water in terms of the charges of the constituent ions, the lattice spacings and the Born radii. 3. The method of Stokes of correlating crystal lattice energies with the self energies of the gaseous ions is updated by using new values of the effective nuclear charge. 4. A simple interrelationship is shown between the gas-phase polarizabilities of molecular liquids and the hard-sphere diameter. (author)