Electronegativity is the ability of molecule to attract an electron to form a covalent deals with atoms in a molecule and their tendancy to attract electrons. An atom's electronegativity is affected by both its atomic number and the distance at which its valence electrons reside from the charged nucleus. The higher the associated electronegativity number, the more an element or compound attracts electrons towards it.In general, electronegativity increases on passing from left to right along a period, and decreases on descending a group. Hence, fluorine is the most electronegative of the elements (not counting noble gases), whereas caesium is the least electronegative
Electronegativity is the tendency to pull the shared pair of electrons toward oneself. those which show the property are electronegative