Question

for each bond, show the direction of polarity by placing a + sign next to the atom expected to have a partial positive charge and a - sign next to the atom expected to have a partial negative charge.
the most polar bond is
(a) te - o
(b) te - se
(c) o - se
use the references to access important values if needed for this question.

Explanation:

To determine the polarity of a bond, we look at the electronegativity difference between the two atoms. The greater the electronegativity difference, the more polar the bond.

Step 1: Recall Electronegativity Trends

Electronegativity generally increases across a period and decreases down a group. Oxygen (O), Selenium (Se), and Tellurium (Te) are all in Group 16. The electronegativity order is \( O > Se > Te \).

Step 2: Analyze Each Bond

• Bond (A): Te - O

Electronegativity of O is much higher than Te. The difference is large.
Polarity: \( \boldsymbol{^{+}Te - O^{-}} \)

• Bond (B): Te - Se

Te and Se are close in electronegativity (both in Group 16, Se above Te). Electronegativity difference is small, so the bond is nearly non - polar.
Polarity: \( Te - Se \) (negligible polarity, no significant \( + \) or \( - \) as the difference is small)

• Bond (C): O - Se

O is more electronegative than Se, but the difference is less than between Te and O (since Se is closer to O in electronegativity than Te is).
Polarity: \( \boldsymbol{^{+}Se - O^{-}} \)

Step 3: Determine the Most Polar Bond

Compare the electronegativity differences:

• \( \Delta\chi(Te - O) \): Largest (since Te is much less electronegative than O).
• \( \Delta\chi(Te - Se) \): Smallest.
• \( \Delta\chi(O - Se) \): Intermediate.

The bond with the largest electronegativity difference is the most polar. So, Te - O has the largest difference.

Answer:

• (A) \( \boldsymbol{^{+}Te - O^{-}} \)
• (B) \( Te - Se \) (negligible polarity)
• (C) \( \boldsymbol{^{+}Se - O^{-}} \)

The most polar bond is (A) Te - O.