Electronegativity increases across a period from left to right in The Periodic table - Reason

 Electronegativity increases across a period from left to right in The Periodic table - Reason

As you move from left to right across a period in the periodic table the Atomic number increases by one unit that means the number of electrons in the shells and the number of protons in the nucleus also increase by one unit but the number of shells in the atom of the elements remain same. Eventually the positive charge in the nucleus increases. This increases the nuclear pull on the valence electrons. Hence the atomic size decreases and the attraction force of the nucleus on the electrons will be high. This results in the increase of Electronegativity of the elements across the period from left to right in The Periodic Table until Group 17.