How to memorize electronegativity charts?

Hint: Electronegativity is the tendency of an atom to attract the shared pairs of electrons towards electrons. Electronegativity increases from left to right and it decreases down the group in the periodic table.


Complete step by step answer:
- Electronegativity increases from left to right across a period because of the increase of the number of the charges on the nucleus which results in the stronger bonding of the electron pair and electronegativity decreases down the group while moving from top to bottom due to the increase in the distance between the nucleus and the valence shell because they decrease the attraction of the electron pair.
- Across a row in the periodic table, the acidic strength increases with the increase in electronegativity. And as we move down the group in the periodic table, the acidic strength increases with the decrease of electronegativity. The reason is that as we move down the group the size of the atom increases due to the addition of new shells and as we move across the period, the size of the atom decreases.

Additional Information :
Some of the examples is mentioned below:
  Ga < Ge
- The Pauling’s electronegativity value of gallium Ga = 1.81
- The Pauling’s electronegativity value of gallium germanium Ge = 2.01
- The value of Pauling’s electronegativity for germanium is greater than that of gallium.

Note: On Pauling's scale the electronegativity of chlorine is more than that of nitrogen but practically we know that the electronegativity of nitrogen is greater than that of chlorine. But while solving the question we should always make sure that the electronegativity of nitrogen is more than that of chlorine.