Question

which of the highlighted chemical bonds in the molecules below is longest? shortest? in between? which highlighted bond requires the highest energy to break? lowest? in between? answer these questions by completing the second and third columns in the table. compound length of highlighted bond energy of highlighted bond h - p - h h h - as - h h h - n - h h

Explanation:

Step1: Recall periodic - trend of atomic radius

Atomic radius increases down a group in the periodic table. The larger the atomic radius, the longer the bond length when bonded to the same atom (in this case, H). N, P, and As are in Group 15. Atomic radius: As > P > N.

Step2: Determine bond - length order

Since the bond is H - X (X = N, P, As), the bond length order is: H - As > H - P > H - N. So, the H - As bond is the longest, H - N is the shortest, and H - P is in between.

Step3: Recall bond - energy relationship with bond - length

Shorter bonds generally have higher bond energies. So, the bond - energy order is: H - N > H - P > H - As. H - N requires the highest energy to break, H - As requires the lowest energy to break, and H - P is in between.

Answer:

compound	length of highlighted bond	energy of highlighted bond
$H - As - H$	Longest	Lowest
$H - N - H$	Shortest	Highest