Which dot-and-cross diagram is correct for \(\mathrm{Al_2Cl_6}\)?
Correct Answer: \( \boxed{\mathrm{B}} \)
\(\mathrm{Al_2Cl_6}\) exists as a dimer of two \(\mathrm{AlCl_3}\) molecules joined by two coordinate (dative covalent) bonds.
Each aluminium atom forms three ordinary covalent bonds with chlorine atoms and accepts one lone pair from a bridging chlorine atom, giving each aluminium an octet.
Therefore, the correct dot-and-cross diagram is (B).
In which structure are three atoms bonded together in a straight line?
Correct Answer: \( \boxed{\mathrm{D}} \)
Consider the molecular geometry of each substance:
Therefore, the correct answer is (D).
Which molecules contain at least one unpaired electron?
1 \(\mathrm{NO}\)
2 \(\mathrm{NO_2}\)
3 \(\mathrm{NH_3}\)
Correct Answer: \( \boxed{\mathrm{B}} \)
Molecules with an odd number of valence electrons usually contain at least one unpaired electron.
Therefore, only statements 1 and 2 are correct, so the answer is (B).
