23. The pair of elements that forms a bond with the greatest electronegativity difference is1 pointK and CaO and ClNa and ClF and Cl

To determine which pair of elements forms a bond with the greatest electronegativity difference, we need to look up the electronegativity values of each element in the pairs given and then calculate the differences.

1. Break Down the Problem

• Identify the elements in each option.
• Find the electronegativity values for those elements.
• Calculate the differences in electronegativity for each pair.

2. Relevant Concepts

Electronegativity is a measure of an atom's ability to attract and hold onto electrons. A large difference in electronegativity between two atoms indicates that they will likely form an ionic bond, while a smaller difference indicates a covalent bond.

3. Analysis and Detail

Let’s identify the elements in each pair and their electronegativity values according to the Pauling scale:

• K (Potassium): 0.82
• Ca (Calcium): 1.00
• O (Oxygen): 3.44
• Cl (Chlorine): 3.16
• Na (Sodium): 0.93
• F (Fluorine): 3.98

Now we evaluate the differences:

1. K and Ca: $|0.82 - 1.00| = 0.18$

2. Na and Cl: $|0.93 - 3.16| = 2.23$

3. F and Cl: $|3.98 - 3.16| = 0.82$

4. Verify and Summarize

Now, we compare the calculated differences:

• K and Ca = 0.18
• Na and Cl = 2.23
• F and Cl = 0.82

The greatest electronegativity difference is from the pair Na and Cl, with a difference of 2.23.

Final Answer

The pair of elements that forms a bond with the greatest electronegativity difference is Na and Cl.