Question Topics: Structure 2.2 The covalent model

Which orbitals overlap to form $\sigma$-bond and $\pi$-bond between carbon and oxygen in methanal?

Which species contain a coordination bond? I. $O_{3}$ II. $CO_{2}$ III. ${NO_{3}}^{-}$

Which statements are correct for the complex ion $[FeCl_{4}]^{2-}$? I. Chloride ions are behaving as ligands. II. The oxidation state