Exemplar Problems

Problem 15 : - Electronegativity increases from left to right across a period because of increasing effective nuclear charge.

• Electronegativity decreases from top to bottom within a group because of increasing atomic size and shielding effect.

Solution :

Electronegativity increases from left to right across a period because of increasing effective nuclear charge:

This is a correct explanation. As you move from left to right across a period, the number of protons in the nucleus (effective nuclear charge) increases, leading to a stronger attraction for electrons in the outermost energy levels. This increased attraction results in higher electronegativity values for elements. Electronegativity decreases from top to bottom within a group because of increasing atomic size and shielding effect: