Question

Rank the following from Longest to Shortest bond length:
i) H-F
ii) As-As
iii) NC
iv) O=O
v) Cl-Cl

Answer 1

This should get you started. The longest bond lengths form the weakest bonds; stronger bonds are shorter.
http://www.science.uwaterloo.ca/~cchieh/cact/c120/bondel.html