Dear manisha, We are glad to help you. Moving from the left to the right of the periodic table, elements of one period get more protons. It means that elements have more positive charge in the nucleus. The increase of positive charge across a period exerts an increasing force of attraction on the electron orbitals. This is why the electronegativity increases from left to right.
expert, i can't understand the line that you wrote while giving the reason for increase in electronegativity in period i.e more positive charges in atom determine the strength of the interaction with negative electrons. please explain it again in detail.
Dear manisha! The reason of increase in electronegativity in period is the increase of proton number in atom: more positive charges in atom determine the strength of the interaction with negative electrons. The decrease of electronegativity in group is caused with the increase of distance between nucleus and electron determined with the electron shield of atom. The most electronegative atom is fluorine. So, it is easy to analyze electronegativity of other atoms using periodic laws.
what are the reasons of increase in electronegativity in period....and also for decrease in group .Why this is so?