Question

check the box before each formula that represents a ligand that is likely to form a complex with a transition metal. if there are none, please check the box below the table.
□ $\ce{no^-_{2}}$
□ $\ce{kbr}$
□ $\ce{feo}$
□ $\ce{h_{2}o}$
□ none of the above

Explanation:

To determine which species are ligands likely to form complexes with transition metals, we analyze each:

• $\ce{NO^-_{2}}$: Nitrite ion has lone pairs (on N or O) to donate, acting as a ligand (e.g., in coordination complexes like $\ce{[Co(NO_{2})_{6}]^{3-}}$).
• $\ce{KBr}$: Ionic compound (K⁺ and Br⁻). Br⁻ could be a ligand, but KBr itself is a salt, not a ligand (ligands are species that donate electron pairs; KBr dissociates, but K⁺ is not a ligand here, and Br⁻ as part of KBr is not acting as a ligand in the compound’s form).
• $\ce{FeO}$: Ionic compound (Fe²⁺ and O²⁻), not a ligand (ligands are neutral or anionic species that donate to a central metal, but FeO is a solid compound, not a species that donates to a transition metal as a ligand).
• $\ce{H_{2}O}$: Water is a classic neutral ligand (donates lone pairs on O) in complexes like $\ce{[Cu(H_{2}O)_{6}]^{2+}}$.

Answer:

• $\boldsymbol{\ce{NO^-_{2}}}$ (check the box)
• $\boldsymbol{\ce{H_{2}O}}$ (check the box)

(Note: $\ce{KBr}$ and $\ce{FeO}$ are not ligands in their given forms, so their boxes remain unchecked. "None of the above" is also unchecked since $\ce{NO^-_{2}}$ and $\ce{H_{2}O}$ qualify.)