How can you describe the arrangement of sodium ions and chloride ions in a crystal of sodium chloride

Sodium chloride is an ionic substance, it is made up of both cations and anions. These ions combined together to form the crystal lattice structure of sodium chloride. In the crystal lattice, each cation of sodium is surrounded by six chloride anions and each chloride ion is in turn surrounded by six sodium ions. The array of ion merge together to form a face centered cubic structure. These ions are held together by strong electrovalent bond.  

"among the transition metal elements, manganese and zinc have a slight lowering of electronegativities. the reason behind this is that the nuclear charges of these elements are slightly weaker than the other transition metal elements due to the way their valence electrons are filled up. both manganese and zinc have their valence electrons filled up to the 4th shell with 1 pair of electrons (4s2) completely occupying it. although the electrons in the 3rd shell (3d) are yet to be paired since the outer most shell is filled up, the ability of the nucleus to attract electrons is lessened. hence,   the electronegativity (or the ability to attract electrons) is lessened."