Of the molecules alc l 3 and alb r 3 , which has bonds that are more polar?

The electronegativity difference of the Al and Cl atoms in AlCl₃ molecule is 1.55 while the electronegativity difference of the Al and Br atoms in AlBr₃ is 1.35

The electronegativity difference of atoms in AlCl₃ molecules is as follows:
3.16 - 1.61 = 1.55
The electronegativity difference of atoms in AlBr₃ molecules is as follows:
2.96 - 1.61 = 1.35

- Both the molecules have a significant amount of difference in the electronegativity of atoms → This shows that both molecules have polar character.

- But, the electronegativity difference in molecule AlCl₃ is 1.55, which is greater than 1.35 of the AlBr₃.

Therefore AlCl₃ is more polar molecule than AlBr₃  

☆ionisation energy increases across a period from na -> ar☆ionisation energy decreases down a group from li -> fr☆ionic radius decreases across a period from na -> cl☆ionic radius increases down a groupfrom f -> ii hope it clarifies your doubts