Regents Chemistry Exam August 2022
37 An atom of which element bonds with an atom of hydrogen to form the most polar bond?
(1) bromine
(2) chlorine (3) fluorine
(4) iodine
Explanation: The most polar bond results from the biggest electronegativity difference. For this question, let's take a look at the Table S on the reference table which lists all the elements and their electronegativity values. Bromine =3.0 Chlorine=3.2 Fluorine = 4.0 Iodine=2.7 Hydrogen = 2.2
Next for each combination of elements we subtract smallest number form the biggest to get the electronegativity difference. For example, HF = 4.0-2.2 = 1.8 Whoever has the largest electronegativity difference, has the most polar bond. HF should be most polar. Alternatively, we might know that fluorine is the most electronegative element on the periodic table and will result in the most polar bond with hydrogen.
Answer: 3