Which of the following elements can have an expanded octet when they form covalent compounds with other elements? A. lodine and chlorine
B. Sulfur and phosphorous
C. Nitrogen and boron
D. Sulfur and nitrogen

B.

Explanation:

Some of the  elements of the third-period and periods below can have expanded octet because they have d- sub-level.

We have 2 possible answers. A and B. Because  lodine and chlorine. Sulfur and phosphorous are  in the 3d or lower periods.

In the compound P2S5, where P forms 5 bonds.

Iodine and chlorine do not have enough difference in electronegativity to form compound ICl7.

So, the answer is B.

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