The force of attraction is given by:
- e²Z/r²
where
r is the distance between the electron and the nucleus (covalent radius).
e is the charge on an electron.
eZ is the charge effective at the electron due to the nucleus and its surrounding electrons.
The quantity Z/r² correlates well with Pauling electronegativities and the two scales can be made to coincide by expressing the Allred-Rochow electronegativity as:
AR=0.744 + 0.359Z/r²
See also: Mulliken scale - Pauling scale