An increase in the ENC gives a greater attraction on the remaining electrons, making the species smaller. The radius of an anion is always larger than the covalent radius of the parent atom. They all have the same number of electrons. It is an isoelectronic series. Ionic compounds are electrically neutral - the number of positive charges equals the number of negative charges.
Ionic compounds have formulas which are empirical formulas.
They contain no molecules. The glue which holds the ions together is a strong electrical attraction between ions of opposite charge. Covalent bonds are formed when 2 atoms share 1 or more pairs of electrons achieving the lowest possible energy. In general, covalent bonds are formed between nonmetal atoms. The lone pairs of electrons are shown as pairs of dots on individual atoms.